A    TE  XT    BOOK 


ON 


WELDING     AND 
CUTTING  METALS 


BY  THE 


Oxyacetylene  Process 


WITH  SIXTY-FOUR  ILLUSTRATIONS 

THIRD  EDITION-REVISED 

Copyrighted  1915 
^y,  C.  H.  BORROWS, r. 


VULCAN  PROCESS  CO. 

MINNEAPOLIS,  MINN. 


PREFACE  TO  THIRD  EDITION. 


It  is  only  a  short  time  since  the  second  edition  was  issued, 
and  it  is  gratifying  to  find  that  the  supply  is  nearly  exhaused. 
There  are  many  mechanics  and  autogenous  welders  who  desire 
short,  clear  and  practical  instructions  on  the  subject  of  oxy- 
acetylene  welding  and  it  is  the  purpose  of  this  book  to  fill  this 
demand. 

A  comprehensive  treatise  on  this  subject  would  necessarily 
include  much  technical  material  that  would  be  useless  to  the  prac- 
tical man  who  wishes  to  acquaint  himself  with  only  enough 
theory  to  thoroughly  master  the  performance  of  his  duties,  and 
for  this  reason  we  have  excluded  nearly  everything  of  a  strictly 
technical  nature. 

The  Chapters  on  chemistry,  physics  and  metals  are  of  the 
most  elementary  nature,  and  cover  in  the  plainest  language 
only  the  subjects  that  are  vital  to  the  welders  information.  At 
the  same  time  they  are  sufficiently  explicit  to  give  him  a  thorough 
working  knowledge  of  the  subjects  that  pertain  to" his  work. 

In  compiling  these  pages  we  have  consulted  the  works  on 
the  Manufacture  and  Properties  of  Iron  and  Steel,  By  H.  H. 
Campbell.  The  Metelftjfgy  qtf  JM1!  &id  Steel,  by  Bradley 
Stoughton,  and  Autqgenous  Welding',  "By^Granzon  and  Rosem- 
berg;  and  some  oi'thb*{^'.rilaji}ij^rt^\  generators  and  welding- 
has  been  condensed  from  papers  which  we  contributed  to  a  few 
of  the  leading  magazines. 

C.  H.  Burrows. 


Ill 
CONTENTS 

Story  of  Vulcan,   (Mythology)   .,  ....VII 

Chapter     1.     The  use  of  the  oxy-acetylene  flame  ...  4 

Chapter     2.     Chemistry  11 

The  Elements,  Table  of  Chemical  Symbols,  and  Atomic  Weights, 
Chemical  Affinity,  The  Atomic  Theory,  Valence,  Reaction,  Com- 
bustion, Flame,  Oxyge;.,  Hydrogen,  Nitrogen,  Calcium  Carbide, 
Acetylene. 

Chapter     3.     Physics    .  25 

Pneumatics,  Boyles  Law,  Heat,  The  Calorie,  The  British  Thermal 
Unit,  Temperature,  Centigrade  and  Fahrenheit,  Table  comparing 
degrees  Centigrade  and  Fahrenheit,  Expansion,  Table  of  Coeffi- 
cients of  Expansion  with  instructions  on  its  use. 

Chapter     4.     Metals  and   their   Properties 

The  Ferrous  Group,  Cast  Iron,  Malleable  Iron,  Wrought  Iron, 
Steel,  The  Blister  Process,  Copper,  Brass,  Aluminum,  Alloys. 

Chapter     5.     Acetylene    Generators   ;  44 

Drip  Type,  Flooding  Type,  Carbide  to  Water  Type,  Selecting  A 
Generator. 

Chapter     6.     Oxy-Acetylene  Welding  and  Cutting 

Torches  ..  -    -50 

Low   Pressure,    High  Pressure,    Cutting  Torches. 

Chapter     7.     Regulators  and  Indicators  .. 

Their   manipulation. 

Chapter     8.     The  Vulcan  Automatic  Acetylene  Generator     61 

Its    operation    and    manipulation. 

Chapter     9.     Operating  Plants  ... 

Compressed   Gas   Plants,    Generator  Plants,    Pipe   installation. 

Chapter  10.     Welding.  Rods   and   Fluxes  ..  68 

The  theory   of  fluxes,    Rods    and   fluxes   for   all   purposes. 

Chapter   11.     Welding  ... 

Oxy-acetylene,  Preheating,  Cast  Iron,  Malleable  Iron,  Steel, 
Aluminum,  Copper,  Brass,  Alloys,  Gold  and  Silver. 

Chapter   12.     Cutting  ...  110 

Theory,  Using  the  torch,  The  Vulcan  torch,  Instructions  on 
Assembling. 

Chapter   13.      Boiler  and  Sheet  Metal  Work  .. 

Preheating  Repair  Work,  Corroded  Mud  Drums,  Inserting  new 
plates  Cutting  door  holes,  man  holes,  etc.,  Patches,  \\elding  m 
flues,  Fabricating  new  work,  Sanction  of  Boiler  Insurance 
Companies. 


Chapter  14.     Carbon    Burning 


126 

Theory,    Cleaning    Auto   Cylinders. 

Useful  Information  and  Tables  128 


342214 


IV 

TABLES. 

Page 

I.  Elements,   their   symbols   ami   atomic    weights 

II.  Weights  of  gases  ...                                                                                 21 

III.  Average  yield  of  gas  from  various  grades  of  carbide 

IV.  Heat  conductivity  of  different  metals  ...  34 
V.  Coefficients  of  expansion   .. 

VI.  Melting  temperature  of  metals 

VII.  Loss   of  pressure   in    pipes    .. 

VIII.  Loss  of  pressure  by  valves  ... 

IX.  Cost  of  oxyacetylene  cutting  ...                                                             114 

X.  Cost  of  cutting  with  oxygen  jet  ...                                                       128 

XL  Cost  of  welding  with  oxyacetylene  torch                                         128 

XII.     Quantity  of  gas  in  cylinders  129 

XIII.  Variation   of  pressure   in   cylinders  129 

XIV.  Comparison  degrees  Centigrade  and  Fahrenheit  130 
XV.     Weight   of   oxygen   drums   130 

XVI.  Consumption  of  gas — and  cost  of  oxyacetylene  welding               131 


LIST  OF  ILLLUSTRATIONS. 

Figure  Page 

1  Broken  locomotive  cylinder 2 

2  Same   cylinder   after   welding   3 

3  Building  in  gear   teeth   , 5 

4  Broken  crank  shaft  - 8 

5  Same    shaft    after    welding    9 

6  Repairing   broken   pump    case    10 

7  Corner  in  chemical  laboratory  15 

8  Phases  of  combustion  17 

9  Oxygen    plant    18 

10  Generator  room  in  electrolytic  oxygen  plant  19 

1 1  Electrolytic   cells  20 

12  High  pressure  pump  for  gas  compression  29 

14  Typical  carbide  to  water  generator  46 

15  Modern   oxyacetylene  welding  torch   50 

16  Oxyacetylene    torch    53 

17  Straight  line  torch 53 

18  Oxyacetylene  cutting  torch   54 

19  Vulcan  combination  cutting  and  welding  torch   55 

20  Toreh   for  welding  machines  57 

21  Automatic    acetylene   regulator 58 

~-  Automatic   Oxygen    Regulator   59 


23  Oxyacetylene  welding  plant  60 

30  Vulcan  automatic  acetylene  generator   ...  61 

31  Vulcan  generator  welding  plant  ...  63 

32  Interior   of   Vulcan   generator   65 

33  Vulcan   portable   generator  plant   67 

23  Welding    table    .  75 

24  Combination   welding   table    76 

25  Oxygen  valve  on  oxygen  drum  slowly  ...  78 

26  Removable  base  for  oxygen  drum  79 

27  Portable  plant  using  dissolved  acetylene  82 

28  Portable   generator   plant    84 

29  Convenient  time  card  86 

34-35  Practical  method  of  beveling  thin  pieces  90 

36  Method  of  beveling  thick  pieces  71 

37-38  Illustrating  economy  of  beveling  on  both  sides  91 

39-40  Effects  of  expansion  and  contraction  92 

41  The  melting  rod  should  not  97 

42  Circular  movement  of  torch  for  work  of  medium  thickness 98 

43  Side  to  side  movement  of  the  torch  for  heavier  welds  99 

44  Position  of  torch  for  filling  holes  100 

45  Crank  shaft  on  V  blocks  prepared  for  welding ...  107 

46  Auto  cylinder  prepared  for  welding  108 

47  Cutting   machine •  113 

48  Cutting   machine    114 

49  Cutting  floor  beams •  115 

50  Cutting  old  boiler  -  116 

51  Cutting  old  boiler  117 

52  i 

53  [   Examples  of  Expansion  ... 

54  \ 

55  Overcoming  effects  of  expansion 

56  Deformation  caused  by  expansion  122 

57 

58 
59 

60  \  Good  and  bad 

61  /  Examples  of  prepared  joints 

62  I 

63  1 

64  / 

65  Carbon   burner   at   work 

66  Fabricating  a  bosh  jacket  


I. 


-.   ! 


VULCAN 


VII 


VULCAN 
The  Roman  God  Of  Fire 

In  olden  days  when  Jupiter,  the  God  of  all  other  Gods,  dwelt 
on  the  celebrated  mountain  Olympus,  and  presided  over  the 
ancient  Romans  ;  when  Neptune  dominated  over  the  sea,  and  the 
beautiful  Diana,  with  her  maidens,  cared  for  all  the  wild  animals 
of  the  forest;  there  came  to  the  family  of  Jupiter  and  his  wife, 
Juno,  a  little  son  whom  they  called  Vulcan. 

Little  Vulcan  possessed  great  powers  and  ability,  but  he  was 
not  a  handsome  child  and  his  mother  Juno,  who  was  disappointed 
in  not  having"  a  more  beautiful  son  to  grace  the  home  of  the 
Gods,  threw  him  down  from  Heaven.  The  infant  God,  falling 
into  the  sea,  was  rescued  and  adopted  by  Thetis,  who  kept  him 
until  he  was  nine  years  old,  and  then  restored  him  to  his  parents. 

Even  in  his  youth,  the  little  God  displayed  wonderful  ability 
at  the  forge  and  all  metallic  handicrafts ;  and  Jupiter,  recognizing 
this  wonderful  ability,  made  him  the  God  of  Fire.  He  later 
erected  forges  and  work  shops  in  which  he  employed  wonderful 
one-eyed  giants,  called  the  Cyclops,  to  assist  him.  In  these  shops 
he  fabricated  many  great  metal  works,  and  one  of  his  prin- 
cipal duties  \vas  to  forge  thunder  bolts  for  his  father  Jupiter. 
Some  claim  his  shops  were  on  Mount  Etna,  where  he  used  the 
heat  of  the  volcano  to  work  his  forges. 

Vulcan  not  only  had  the  ability  to  make  the  hottest  fires  and 
forge  the  most  difficult  metal  objects;  but  he  was  artistic  by  na- 
ure;  so  when  Jupiter  wished  to  provide  the  earth  with  the  first 
mortal  woman,  Vulcan  fashioned  her  out  of  clay,  and  the  Gods 
animated  the  statue.  So  his  wonderful  work  is  handed  down  to 
the  present  day  in  the  grace  and  beauty  of  our  women. 

In  honor  of  this  Roman  God,  we  have  dedicated  this  book  and 
named  our  process,  which  develops  the  hottest  flame  known,  and 
causes  the  hardest  metals  to  flow  like  wax,  to  Vulcan  the  God 
of  Fire  and  Patron  of  all  metallic  handicraft ! 

Vulcan  Process  Co. 


\ 


WELDING  AND  CUTTING  METALS 

BY  THE 

OXYACETYLENE  PROCESS 


.).\  >'  ACETYLENE    WELDING    AND    GUTTING 


^ 


TIG.  1. 
BROKEN  LOCOMOTIVE  CYLINDER. 

This  illustration  shows  the  cylinder  after  the  edges  of  the  fracture 
had  been  chipped  for  welding. 

The  bar  across  the  front  and  a  similar  bar  across  the  rear  was  used  to 
support  a  temporary  grate,  upon  which  the  preheating  fire  was  built. 


OXY-ACETYLENE  WELDING  AND  CUTTING 


FIG.  2. 
LOCOMOTIVE  CYLINDER  AFTER  WELDING. 


This  illustrates  the  same  cylinder  shown  in  Fig.  1,  with  a  new  cast 
iron  piece  welded  in  the  fracture.  Ordinarily  the  old  piece  is  used  to 
make  the  mend,  but  in  this  ease  the  old  piece  had  been  destroyed  by 
repeated  attempts  to  weld  it  in  with  thermit. 


4  OXY-Al'KTYLKXE    WELDING    AM)    CUTTING 

CHAPTER  I. 
THE  USE  OF  THE  OXY-ACETYLENE  FLAME. 

The  oxy-acetylene  welding  and  cutting  torch  has  become 
so  popular  in  the  last  few  years,  that  almost  every  issue  of 
the  trade  papers  in  any  branch  of  work  contains  interesting 
accounts  of  new  successes  in  the  use  of  this  powerful  tool. 
The  first  application  of  the  process,  to  commercial  use,  dates 
back  to  1903,  and  its  rapid  growth  in  popularity  is  due  to  the 
ease  and  economy  with  which  its  intense  heat  is  applied  to 
any  of  the  metal  trades,  to  join  two  pieces  by  welding,  or 
separate  them  by  cutting  without  the  stroke  of  a  hammer. 

A  notable  example  of  the  saving  that  may  be  effected  by 
using  this  process  is  in  the  event  of  repairing  a  broken  loco- 
motive cylinder  shown  in  Fig.  i.  This  cylinder  had  a  piece 
broken  out  of  the  wall  including  a  portion  of  the  flange. 
Previous  attempts  to  weld  this  piece  in  place  by  other  methods 
had  proven  disastrous,  and  resulted  in  making  the  fracture 
larger.  The  oxy-acetylene  process  was  then  'brought  into  use, 
and  in  less  than  a  day's  time  a  new  piece  was  welded  in  as 
shown  in  Fig.  2.  The  cylinder  was  rebored,  drilled,  and  the 
job  finished  without  removing  it  from  the  locomotive.  A 
great  saving  in  this  case  is  credited  to  the  fact  that  the  loco- 
motive was  put  back  into  service  in  a  comparatively  short 
time,  and  the  repairs  were  made  without  dismantling.  The 
durability  of  this  work  is  illustrated  in  fact  that  this  cylinder 
was  welded  July  loth,  1910,  and  is  still  in  successful  operation. 

Very  often  small  pieces  of  a  machine  are  broken  off  and 
lost,  and  in  consequence  the  whole  machine  is  out  of  use.  In 
such  cases  it  is  not  always  necessary  to  have  the  missing  piece 
with  which  to  make  repairs,  but  the  missing  portion  may  be 
built  on  with  similar  material  melted  from  the  welding  rod. 
A  good  example  of  cases  where  this  process  is  appliable  is  in 
building  new  teeth  into  a  broken  gear  or  sprocket  wheel,  build- 
ing up  lugs  or  adding  new  material  to  parts  that  are  badly  worn. 
There  are  innumerable  instances  where  the  addition  of  a  little 
metal  will  save  much  expense  and  long  delays,  and  in  the  opera- 


TIIK  t'SK  OF  THK  OXY-ACKTVLKNK  FLA.MK 


FIG.  3. 
BUILDING   IN   GEAR    TEETH. 

In  this  process  the  old  teeth  are  not  required  to  make  the  mend,  but 
new  material  is*  built  up  to  form  a  new  tooth. 

tion  of  contractors  who  are  remote  from  their  base  of  supplies, 
this  sometimes  amounts  to  quite  an  item. 

Large  shipyards,  railroad  shops,  contracting  engineers, 
as  well  as  the  smaller  institutions,  machine  shops,  boiler  shops, 
foundries,  garages  and  'blacksmiths,  all  find  this  powerful  flame 
indispensable  for  sure,  quick  and  economical  results.  In  proof 
of  this  statement  it  is  well  to  cite  experiments  made  at  dif- 
ferent times,  and  in  different  places  by  two  of  our  foremost 
railway  systems.  These  experiments  were  very  carefully  con- 
ducted through  a  period  of  14  days  to  ascertain  to  a  certainty 


(J  OXY-ACETYLEXE    WELDING    AND    CUTTING 

the  exact  economic  value  of  this  process.  Every  item  of  cost 
was  carefully  checked  against  the  records  of  former  methods, 
and  the  results  showed  an  average  saving  of  $155  a  day,  for 
each  day  the  test  continued. 

This  immense  daily  saving  was  made  possible  by  having 
plenty  of  work  on  which  to  use  the  process,  but  the  condi- 
tions were  far  from  ideal,  and  it  is  safe  to  say,  had  the  condi- 
tions been  more  favorable  this  figure  could  have  been  nearly 
doubled. 

Another  field  where  this  tool  is  finding  great  favor  is  in 
cutting  iron  and  steel  structures,  heavy  plates,  door  holes  01 
man  holes  in  boilers,  and  in  cutting  up  the  wreckage  of  steel 
structures  which  have  been  destroyed  by  fire  or  wind.  A  re- 
cent incident  where  the  oxy-acetylene  torch  proved  to  be  valu- 
able for  this  work,  occurred  in  the  harbor  at  Duluth  where 
the  wind  destroyed  several  large  steel  docks.  It  is  difficult 
to  imagine  the  bewildering  entanglement  of  steel  'bars,  beams 
and  angles  all  piled  up  in  a  huge  irregular  mass.  Heavy  steel 
members  were  twisted  and  interlaced  with  smaller  members 
in  such  a  way  that  they  could  not  be  removed  without  cutting, 
and  to  cut  them  with  a  sharp  edge  tool  was  next  to  impossible. 
The  only  tool  suitable  for  this  work  was  the  oxy-acetylene 
cutting  torch,  and  it  was  employed  with  very  economic  ad- 
vantage. 

Another  occasion  where  this  torch  became  conspicuous 
was  in  cutting  up  the  wreckage  of  a  steel  freight  steamer, 
which  was  sunk  on  the  east  coast  about  a  year  ago.  The 
vessel  had  broken  up  and  lay  in  pieces  in  about  30  feet  of 
water.  The  pieces  weighing  25  to  40  ton  were  a  shapeless 
mass,  with  the  plates,  beams,  and  members  bent  and  crumpled. 
The  plates  forming  the  shell  of  the  boat  were  about  %  in. 
thick  at  the  top  and  on  the  sides,  but  on  the  bottom  they 
were  much  heavier.  The  rivets  could  not  be  removed,  since 
in  many  cases  the  flanges  of  angles  and  pieces  of  plates  were 
bent  over  against  them,  preventing  access  to  their  heads.  The 
condition  of  the  steel  was  such  that  the  expense  of  ordinary 
hand  cutting  would  have  been  prohibitive,  and  the  wreckage 


THE  USE  OF  THE  OXY-  ACETYLENE  FLAM  K  7 

would  have  been  a  total  loss  had  the  oxy-acetylene  torch  not 
been  available. 

An  idea  may  be  formed  of  the  speed  and  ease  with  which 
steel  plates  can  be  cut  by  this  process  from  the  following- 
figures  : 

Plates  y2  inch  thick  —  30  inches  per  minute. 

Plates  i       inch  thick  —  20  inches  per  minute. 

Plates  V/2  inch  thick  —  16  inches  per  minute. 

Plates  2     inch  thick  —  12  inches  per  minute. 

This  information  is  tabulated  in  the  back  of  the  book. 

To  obtain  a  comparison,  in  time  and  cost,  between  cutting 
by  hand  in  the  usual  way,  and  doing  the  same  work  with 
the  oxy-acetylene  cutting  torch,  careful  observations  were 
made  and  recorded,  as  outlined.  Cutting  a  full  door  patch 
for  boiler  by  the  old  method  required  six  hours  time  for  a 
boiler  maker  and  his  helper  at  a  cost  of  $4.04.  Doing  the 
same  job  with  the  cutting  torch  required  nine  minutes  time 
of  one  man  and  cost  2$c.  Cutting  a  side  sheet  and  door  sheet 
by  the  old  method,  required  eighteen  hours  for  a  boiler  maker 
and  his  helper,  and  cost  $12.15.  Doing  the  same  work  with 
the  cutting  torch  required  one-half  hours  time  of  one  man  and 
cost 


These  two  comparisons  were  not  selected  to  favor  one 
cause  or  the  other,  but  were  taken  at  random  from  a  list  of 
many  similar  operations. 


OXV-ACKTYLKNE    WKLDIXG    AND    CUTTING 


FIG.  4. 
BROKEN   CRANK   SHAFT. 

The  illustration  shows  a  six  inch  crank  shaft  being  brought  into  shop 
preparatory  to  welding. 

The  illustration  Fig.  4  shows  a  crank  shaft  six  inches  in 
diameter  and  eleven  feet  long.  It  was  a  member  in  a  three 
cylinder  100  H.  P.  producer  gas  engine,  belonging  to  a  single 
unit  electric  light  plant,  and  was  broken  square  off  through 
one  of  the  arms,  totally  disabling  the  entire  plant.  It  was 
taken  to  a  welding  shop  and  with  the  oxy-acetylene  torch  the 
complete  job  was  welded  and  ready  to  deliver  in  less  than 
twenty-four  hours,  at  a  cost  of  about  $26.00.  A  detail  of  this 
cost  is  as  follows: 

8  hours  welding  time @  35c  $2.80 

817  ft.  Oxygen   @  O2c  16.34 

812  ft.  Acetylene   @  oo.8c—  6.49 

50  Ibs.  Charcoal @  QIC  .50 

After  cooling,  the  weld  was  found  to  be  perfectly  homo- 
geneous in  texture,  void  of  fire-scale,  or  oxidation,  and  ma- 
chined freely.  This  crank  shaft  has  since  been  in  heavy  service 
for  a  year  or  more  and  is  giving  perfect  satisfaction. 


THI-:    l*SK    OF    THK    OX  Y-ACKTYLKN  K    FLAMK 


FIG.  5, 
CKANK  SHAFT  AFTER  WELDING. 

The  charcoal  itemized  in  cost  was  used  for  preheating  pur- 
poses. The  little  white  cross  indicates  the  place  where  the  weld 
was  made. 


10 


OXY-ACETYLKNE    WELDING    AND    CUTTING 


FIG.  6. 
REPAIRING  BROKEN  PUMP  CASE  BY  AUTOGENOUS  WELDING. 

In  this  illustration  the  plate  which  is  shown  bolted  temporarily  in  the 
opening  of  the  pump  case,  was  used  as  a  grating  to  support  the  preheating 
fire. 


11 
CHAPTER  II. 

CHEMISTRY. 

Origin.  The  practical  part  of  this  science  existed  previous 
to  the  theoretical ;  and  may  be  traced  to  Tubal  Cain,  the  father 
worker  of  metals,  but  by  degrees,  as  men  began  to  think  they 
also  began  to  observe  and  theorize. 

Thinking  men  saw  that  a  gross  earthy  matter,  such  as  iron 
ore,  became  changed,  by  fire,  into  a  hard  metallic  substance 
like  iron,  and  upon  these  observations  was  built  the  most  per- 
fectly systematized  and  exact  science  of  the  day. 

The  Elements: — In  the  earth  are  millions  of  chemical  com- 
pounds which  are  mixed  together  to  form  the  air,  the  waterr 
the  minerals  or  animal  and  vegetable  life,  and  all  of  these  com- 
pounds are  capable  of  being  separated  into  more  simple  sub- 
stances called  "elements."  For  example  water  may  be  separ- 
ated into  hydrogen  and  oxygen.  Acetylene  gas  may  be  sep- 
arated into  the  simpler  substances,  carbon  and  hydrogen.  In 
these  examples  the  water  and  acetylene  are  chemical  com- 
pounds, but  the  hydrogen,  oxygen  and  carbon  are  elements 
and  are  not  capable  of  being  separated  into  more  simple  sub- 
stances. These  elements  may  be  separated  into  atoms,  but 
all  the  atoms  of  any  one  element  are  alike  in  size  and  weight,, 
and  are  composed  of  the  same  single  substance  as  the  element 
which  it  composed.  Then  we  may  say  that  an  element  is  a  single, 
simple  substance,  which  is  dissimilar  to,  and  incapable  of  being 
separated  into,  any  other  substance. 

Chemical  Symbols. — The  earlier  chemists  employed  the 
signs  of  the  planets  to  represent  the  metals;  thus,  silver  was 
the  moon,  hence  the  expression  "silvery  moon,"  and  the  term 
"lunar  caustic"  for  silver  nitrate.  In  the  modern  science  each 
of  the  elements  are  represented  by  one  or  two  initial  letters 
called  "symbols"  taken  from  the  Latin  name  of  the  element. 
The  symbol  for  iron  is  Fe,  because  the  Latin  name  of  iron 
is  ferrum.  That  for  oxygen  is  O ;  for  hydrogen  is  H ;  for  car- 
bon is  C ;  and  for  calcium  is  Ca. 


OXY-ACETYLKNK    WELDING    AND    CUTTING 


Arsenic   

As 

75 

Barium   

Ba 

137.4 

Bismuth   

Bi 

208 

Boron  

B 

11 

Calcium  

.Ca 

40 

Carbon  

C 

12 

Chlorine  

Cl 

35.5 

Chromium  

Cr 

52 

Cobalt  

Co 

59 

Copper  

Cu 

63.6 

Fluorine   

F 

19 

Gold  

.Au 

197 

Hydrogen  _  

H 

1 

Iodine  _  

I 

127 

Irone  

Fe 

56 

Lead   

..:....Pb 

207 

Magnesium  

Mg 

24 

A  table  of  about  one-half  of  the  known  elements  is  arranged 
below  showing  their  symbols  and  atomic  weights. 

TABLK  I. 
ELEMENTS,  THEIR  SYMBOLS  AND  ATOMIC  WEIGHTS. 

Manganese  Mn  55 

Molybdenum    Mo  96 

Nickel  Ni  59 

Nitrogen  N  14 

Oxygen  O  16 

Phosphorus P  31 

Potassium  K  39 

Silic  on  Si  28.4 

Silver Ag  108 

Sodium  .Na  23 

Sulphur  _..S  32 

Tin  : Sn  118.5 

Titanium  • Ti  48 

Tungsten  Wo  184 

Vanadium  V  51 

Zinc   ...  Zn  65.4 


Chemical  Notation. — The  principles  upon  which  the  modern 
chemical  notation  is  founded,  is  that  each  symbol  indicates 
one  or  more  atoms  of  the  element  it  represents,  thus  C,  C2,  C2/ 
indicate  respectively,  one,  two  and  twenty-seven  atoms  of  car- 
bon.. Two  symbols,  placed  side  by  side  signifies  that  they  are 
in  close  chemical  union;  thus  CO  signifies  a  compound  con- 
taining an  atom  of  carbon  and  an  atom  of  oxygen.  C2  H2 
signifies  that  two  atoms  of  carbon  are  in  chemical  union  with 
two  atoms  of  hydrogen,  forming  one  molecule  of  acetylene. 
When  symbols  are  separated  by  the  sign  -f-  it  signifies  that 
the  atoms  thus  separated  are  not  in  chemical  union  to  form 
one  substance ;  but  are  mingled  and  still  exist  as  separate  sub- 
stances, thus  C2  H2  -f  O2  signifies  that  one  molecule  of  acety- 
lene is  mixed  with  two  atoms  of  oxygen.  A  number  placed 
on  left  of  a  group  of  symbols  signifies  that  the  whole  group, 
as  far  as  the  next  comma  or  plus  -f-,  is  to  be  multiplied  by  it; 
thus  2  CO  signifies  that  one  atom  of  carbon  and  one  atom  of 
oxygen  are  combined  to  form  one  molecule  of  carbon  monoxide 
arid  that  two  of  those  molecules  are  represented.  The  expres- 
sion H2  -{-  2  CO,  signifies  that  two  atoms  of  hydrogen  are 


CHEMISTRY  ].">, 

mingled  with  two  molecules  of  carbon  monoxide.  The  sign  = 
signifies  a  reaction  or  the  result  of  mingling  the  atoms  or 
molecules  of  different  substances;  thus,  C2  H2  -(-  O2  ==  If 2  -|- 
2  CO  signifies  that  if  one  molecule  of  acetylene  becomes 
mingled  with  two  atoms  of  oxygen,  there  will  'be  a  chemical 
union  in  which  two  atoms  of  carbon  unite  with  two  atoms 
oxygen,  forming  two  molecules  of  carbon  monoxide  and  liber- 
ating the  two  atoms  of  hydrogen,  which  become  mingled  with 
the  monoxide  in  an  uncombined  state. 

Chemical  Affinity. — The  attraction  that  causes  elements  to 
unite  and  form  new  substances,  like  water,  acetylene  or  car- 
bon monoxide,  and  afterwards  holds  them  together,  is  called 
chemical  affinity.  Some  elements  apparently  have  no  affinity 
for  each  other,  while  others  have  a  tremendous  affinity.  Some 
elements  have  an  affinity  for  each  other  under  certain  in- 
fluences, and  will  unite  forming  new  substances,  but  under 
other  influences  this  affinity  may  be  destroyed  and  the  sub- 
stances separated  again  into  their  original  elements.  Some 
of  the  more  common  influences  which  may  effect  the  affinity 
of  elements  are  heat,  pressure  and  an  electric  current. 

To  start  chemical  union  it  is  sometimes  only  necessary  to 
mix  two  substances  together  and  they  will  unite  and  form 
a  new  substance.  In  this  instance  the  elements  are  held  to- 
gether by  affinity.  If  this  substance  be  mingled  with  another 
element  under  a  different  influence  it  may  !become  separated 
and  one  of  its  elements  unite  with  the  newly  added  element. 
Take  for  instance  acetylene,  which  is  composed  of  two  atoms 
of  hydrogen  and  two  atoms  of  carbon  held  together  by  af- 
finity. Under  ordinary  conditions  this  union  is  stable  and 
the  acetylene  may  be  mixed  with  oxygen  without  forming 
any  new  substance ;  but  if  heat  or  pressure  is  applied  the  car- 
bon will  leave  the  hydrogen  and  unite  with  the  oxygen.  The 
result  in  case  of  applied  pressure  would  be  an  explosion. 

The  Atomic  Theory.— Prom  the  foregoing  it  is  observed 
that  the  union  of  atoms  to  form  new  substances  is  represented 
by  a  group  of  symbols,  to  which  are  attached  various  signs 


14  OXY-ACETYLENE    WELDING    AND    CUTTING 

and  figures.  This  group  of  symbols  and  figures  is  called  a 
•chemical  formula.  Let  us  study  these  formulas  a  little  farther. 
Take  for  instance  C2  H2,  from  the  table  of  atomic  weights 
we  find  the  atomic  weight  of  C  =  =12,  and  H  =  I  ;  then  form 
this  formula  C2  H2  we  may  derive  four  thoughts : 

(1)  the  formula  represents  I  molecule  of  acetylene. 

(2)  one  molecule  of  acetylene  contains  two  atoms  of  carbon 
and  two  atoms  of  hydrogen. 

(3)  one  molecule  of  acetylene  is  composed  of  24  parts  by 
weight  of  carbon,  and  2  parts  by  weight  of  hydrogen. 

(4)  by  weight,  acetylene  contains  26  parts. 

If  the  formula  and  atomic  weights  are  known,  the  percentage 
of  the  composition  may  be  calculated  as  follows : 

C  =  2  x  12  =  24  or  24  parts  by  weight  of  carbon      ;__- 
H  =  2  x     i=     2  or     2  parts  by  weight  of  hydrogen. 

26  parts  by  weight  in  acetylene- 

24 

-  =  .923  or  92%  carbon  by  weight 
26 

2 

-  =  .07692  or  8%  hydrogen  by  weight 
26 

Valence. — Atoms  differ  with  respect  to  the  number  of  atoms  of 
other  elements  with  which  they  will  combine.  This  difference 
in  combining  power  is  indicated  by  the  term  valence. 

The  valence  of  an  element  is  the  number  of  hydrogen  atoms 
•with  which  its  atom  will  unite,  or  replace. 

In  water  H2  O  we  find  that  one  atom  of  oxygen  will  unite 
with  two  atoms  of  hydrogen,  therefore  we  say  the  valence  of 
oxygen  is  II.  The  valence  of  carbon  is  IV.  and  of  calcium  is  II. 
This  means  that  one  atom  of  carbon  will  unite  with  or  replace 
four  atoms  of  hydrogen,  and  an  atom  of  calcium  will  unite  with 
or  replace  two  atoms  of  hydrogen. 

The  application  of  valence  is  useful  in  writing  formulas  and 


CHEMISTRY 


15 


determining  reactions.  Thus,  knowing  that  the  valence  of  car- 
bon is  IV,  we  know  each  atom  of  carbon  will  unite  with  four 
atoms  of  hydrogen,  and  since  the  valence  of  oxygen  is  II  each 
atom  of  oxygen  will  replace  two  atoms  of  hydrogen.  Then  in 
the  reaction  C2  H2  +  O2  =  H2  +  2  CO,  as  stated  on  page  14, 
we  know  the  final  H2  will  unite  with  one  more  atom  of  oxygen 
and  the  final  2  CO  will  unite  with  two  more  atoms  of  oxygen. 

The  complete  reaction  may  be  expressed  as  follows: 
C2  H2  +  O2  =  H2  +  2CO 
H2  +  O  ==  H2  O  ==  one  molecule  water 
2  CO  +  O2  =  2  (CO2)  =  two  molecules  carbon  dioxide 


FIG.  7. 
CORNER  IN  CHEMICAL  LABORATORY. 


16       'OXY-ACETYLKNK  WELDTXG  AND  CUTTING 

Reaction. — The  combination  of  elements  to  form  a  new  sub- 
stance is  called  reaction.  The  term  expresses  a  chemical  union 
in  which  the  resulting  substance  has  properties  different  from  the 
elements  which  compose  it. 

If  the  elements  are  mingled  without  chemical  union,  there 
is  said  to  be  no  reaction.  Thus  if  finely  ground  sulphur  be  mixed 
with  finely  ground  iron  no  new  properties  are  produced,  and 
we  say  no  reaction  has  taken  place,  but  if  we  heat  the  mixture 
a  chemical  action  takes  place  in  which  the  elements  unite  to  form 
a  new  substance.  Then  we  say  there  has  been  a  reaction. 

When  reactions  produce  heat,  they  have  chemical  energy. 
which  can  be  transferred  into  other  forms  of  work.  Not  all 
reactions  produce  heat,  but  some  are  accompanied  by  a  consump- 
tion of  heat,  and  therefore  use  up  energy,  or  rather  they  trans- 
form energy  into  chemical  work.  This  heat  energy  is  not  lost 
for  we  can  get  it  back  by  reversing  the  action. 

Combustion. — Combustion  is  a  reaction  in  which  a  fuel  (com- 
bustible) unites  with  oxygen  and  produces  heat.  There  are  sev- 
eral elements  that  will  react  with  oxygen  in  this  way.  Foremost 
among  these  are  carbon,  hydrogen  and  iron.  When  there  is  just 
the  right  amount  of  both  oxygen  and  combustible  to  cause  reac- 
tion, we  have  perfect  combustion;  but  if  there  is  an  excess  of 
either  element,  we  have  incomplete  combustion.  Incomplete  com- 
bustion always  results  in  loss  of  heat. 

Flame. — When  reaction  is  very  rapid,  the  heat  developed  may 
cause  the  gaseous  elements  to  glow  like  white  hot  iron.  These 
glowing  gases  are  flame.  Flame  has  three  distinct  parts :  the 
central  or  non-luminous  part,  where  there  is  no  combustion,  but 
where  the  carbon  begins  to  separate  from  the  hydrogen;  the 
second  or  luminous  part,  where  the  carbon  is  for  a  moment  free 
and  heated  to  a  white  heat;  and  the  exterior  part,  which  is  the 
hottest,  and  where  combusion  is  complete.  The  foregoing  is  true 
with  the  ordinary  flame  where  the  oxygen  is  derived  from  the 
atmosphere  and  combustion  takes  on'  the  exterior;  but  in  the 
oxy-acetylene  flame  the  oxygen  is  supplied  in  a  pure  state  and 
mingled  with  the  combustible  before  it  is  ejected  from  the  torch. 
This  causes  very  rapid  reaction  and  intense  heat,  and  in  this 


CHEMISTRY  17 

case,  since  the  reaction  is  at  the  interior  the  hottest  part  is  at  the 
point  of  greatest  illumination.  It  is  easy  now  to  understand  of 
what  importance  is  the  form  of  the  burner,  and  how  we  may 
modify  it  accordingly  as  we  want  light  or  heat.  If  we  wish  light 
the  carbon  must  be  protected  for  a  moment  while  it  is  in  the 
glowing  state,  but  not  long  enough  for  it  to  pass  off  unconsumed. 
If,  on  the  contrary,  heat  is  desired,  the  carbon  must  be  burned  as 
rapidly  as  possible. 


CO+OCO2" 
0=H20? 


FIG.  8. 
PHASES  OF  COMBUSTION  IX  OXY-ACETYLENE  FLAME. 


of  trm  ports  described  on  pag**  17,  the  oxy-acety- 
lene  flame  is  divided  into  two  very  distinguishable  parts,  the 
inner  flame,  where  the  oxygen,  supplied  by  the  torch,  reacts  with 
the  carbon  in  the  acetylene,  producing  carbon  monoxide,  and 
setting  the  hydrogen  free  ;  and  the  outer  flame  where  the  carbon 
monoxide  and  hydrogen  reacts  with  the  oxygen  supplied  by  the 
atmosphere.  The  inner  flame  is  of  a  dazzling  white,  but  the 
outer  flame  has  a  bluish  tinge,  .due  to  the  combustion  of  hydro- 
gen, surrounded  by  a  yellow  flame  due  to  the  combustion  of  car- 
bon monoxide.  The  temperature,  taken  at  the  extremity  of  the 
white  jet,  is  very  much  higher  than  that  of  any  other  flame,  and 
is  calculated  to  be  6300  degrees  F. 

To  attain  this  temperature  without  waste  of  gases,  the  torch 
must  be  constructed  on  highly  scientific  principles.  The  size  of 
the  openings,  the  mixing  chamber,  pressures  of  gases,  are  all 
factors  to  be  considered  in  its  design. 

OXYGEN. 

Oxygen  is  an  odorless,  colorless,  tasteless  gas.  It  is  mingled 
with  nitrogen  in  the  air,  and  combined  with  hydrogen  in  water.  It 
is  united  with  nearly  all  the  minerals  in  their  native  state,  and  is 
the  most  abundant  element  known  to  us.  At  ordinary  tempera- 


IS 


OXY-ACETYLENE    WELDING    AND    CUTTING 


tures  it  forms  few  chemical  reactions,  but  when  heated,  is  one  of 
the  most  active  elements,  vigorously  reacting  with  hy- 
drogen and  carbon,  as  well  as  their  compounds  in  the  form  of 
gases. 

When  oxygen  reacts  with  an  element  the  product  is  called 
an  oxide,  and  the  process  is  said  to  be  oxidation.  When  iron  is 
red  hot  it  oxidizes  very  rapidly.  The  welder  should  therefore 
adjust  his  torch  to  procure  a  perfectly  neutral  flame,  with  just 
enough  oxygen  to  consume  the  acetylene. 

Oxygen  is  prepared  in  a  variety  of  ways,  giving  as  great  a 
variety  in  percentage  of  purity.  For  commercial  purposes  it  may 
be  made  from  chlorate  of  potash  and  manganese  dioxide  in  the 
proportions  of  100  pounds  of  the  chlorate  of  potash  to  13  pounds 
of  the  manganese  dioxide.  These  two  chemicals  are  first  thor- 
oughly mixed,  and  then  placed  in  a  retort  and  heated.  This  lib- 
erates the  oxygen,  which  passes  off  through  washers  to  storage 
tanks.  The  cost  of  producing  oxygen  in  this  way,  depends  on  the 
price  of  chemicals.  With  chlorate  of  potash  at  9^0  per  pound 
and  manganese  dioxide  at  2%c  per  pound,  the  cost  would  aver- 
age 4C  per  cubic  foot,  including  cartage,  shop  expense,  etc. 


FIG.  9. 
OXYGEN  PLAN. 

l*siii.Lf  <'ryst;illi/e<l  Chlorate  of  Potash  and  Manganese  Dioxide. 


CHEMISTRY  19 

O.rygen  from  Air. — Oxygen  may  also  be  extracted  from  air. 
If,  by  means  of  combined  pressure  and  cold,  air  be  converted  into 
a  liquid,  its  two  components  may  be  separated  by  centrifugal 
force,  or  else  the  nitrogen  may  be  allowed  to  evaporate  leaving 
the  liquid  oxygen  behind.  No  chemical  processes  are  necessary 
for  this  separation  because  the  elements  are  not  combined. 


FIG.  10. 
GENERATOR  ROOM  IN  ELECTROLYTIC  OXYGEN  PLANT. 

-Oxygen  by  Electrolysis  of  Water. — Oxygen  and  hydrogen 
are  liberated  when  an  electric  current  is  passed  through  acidu- 
lated water.  The  apparatus  first  used  for  this  purpose  consisted 
of  a  vessel  containing  water  and  having  suspended  therein,  two 
test  tubes  with  their  open  end  submerged.  Positive  and  nega- 
tive electrodes  were  placed  just  beneath  the  opening  in  the  tubes, 
and  when  an  electric  current  was  caused  to  flow  through  the 
water  between  the  electrodes,  oxygen  was  liberated  at  the  nega- 
tive pole,  and  hydrogen  at  the  positive  pole.  These  gases  ascended 
and  were  gathered  in  the  tubes. 


20  OXY- ACETYLENE    WELDING    AND    CUTTING 

Although  the  production  of  oxygen  and  hydrogen,  by  the 
electrolysis  of  water,  is  one  of  the  oldest  electrochemical  experi- 
ments, it  was  not  until  recent  years  that  the  process  was  made 
economically  practical.  There  was  considerable  difficulty  in 
developing  an  apparatus  that  would  operate  successfully  in  prac- 
tice. One  of  the  hardest  conditions  to  meet  was  the  necessity  of 
absolute  safety.  The  problem  has  now  been  worked  out  satisfac- 
torily so  that  large  scale  electrolysis  of  water  is  on  a  solid  indus- 
trial basis.  Oxygen  made  by  this  process  is  most  pure  and  best 
adapted  to  oxy-acetylene  welding. 


FIG.  11. 
ELECTROLYTIC  CELLS  FOR   GENERATING   OXYGEN. 

HYDROGEN. 

Hydrogen  is  a  colorless,  tasteless,  odorless  gas,  and  the  light- 
est substance  known.  By  weight  it  forms  n  per  cent  of  water, 
ancl  8  per  cent  of  acetylene.  Hydrogen  also  exists  in  all  living 
forms.  It  has  a  high  chemical  affinity  for  oxygen,  and  burns 


CIIKMISTRY 


with  it  at  a  temperature  of  about  4100  degrees  F.  When  used 
in  the  cutting  torch  with  oxygen  it  is  a  very  satisfactory  fuel  for 
cutting  the  ferrous  metals.  Hydrogen  is  obtained  in  its  purest 
form  by  the  electrolysis  of  water. 


NITROGEN. 

Nitrogen  is  a  colorless,  tasteless,  odorless  gas,  forming  77 
per  cent  of  air.  It  is  of  no  benefit  to  the  oxy-acetylene  welder,  in 
fact  it  is  a  detriment  since  it  does  not  support  combustion  but 
absorbs  heat  from  the  flame. 


TABLE  II. 
WEIGHTS  OF  GASES. 


Name 
of 
Gas 

At    32°    P   and   14.7   Ibs.    pressure 

Specific 
Gravity 

Volume 
of   one  pound 
cubic    foot 

Weight 
of   one 
cubic    foot 

Oxygen  
Air  
Hydrogen  
Nitrogen  
Acetylene    .. 

1.104 
1. 
.069 
.972 
.91 

11.2056 
12.388 
178.891 
12.7226 
13.6126 

.08925 
.08073 
.00559 
.0786 
.07346 

CALCIUM  CARBIDE 

Calcium  is  the  metal  that  exists  in  lime.  Its  symbol  is  Ca. 
Carbon,  a  solid  but  not  a  metal,  occurs  in  the  earth  in  crystallized 
form  as  graphite  and  as  diamonds.  It  is  also  the  fuel  element 
in  coal.  The  symbol  for  Carbon  is  C. 

Calcium  Carbide  (Ca  C2)  is  a  compound  of  Calcium  and 
Carbon  in  the  proportions  of  62  per  cent  calcium  to  38  per  cent 
carbon  which  combine  to  form  a  hard  crystalline  substance  of  a 
dark  gray  color.  *In  describing  the  manufacture  of  calcium  car- 
bide it  is  well  for  the  reader  to  remember  that  the  materials 
employed  are  among  the  most  refactory  ones  which  we  know 
Lime  is  so  infusible  that  it  is  frequently  employed  for  the  material 
of  crucibles  in  which  the  highest  melting  metals  are  fused,  and 

*From  bulletin  of  the  department  of  chemistry.     Pennsylvania  State 
College. 


22  OXY-ACETYLENE    WELDING    AND    CUTTING 

for  pencils  in  the  calcium  light,  because  it  is  capable  of  with- 
standing extremely  high  temperatures.  Carbon  is  the  material 
employed  in  the  manufacture  of  arc  lights,  and  other  electric 
appliances  for  the  same  reason.  Yet  in  the  manufacture  of  car- 
bide these  two  most  refractory  substances  are  forced  into  com- 
bination with  each  other. 

It  is  the  excessively  high  temperature  attainable  in  the  mod- 
ern electric  furnace,  five  to  seven  thousand  degrees  Fahrenheit, 
which  alone  accomplishes  the  combination  of  these  elements  to 
form  calcium  carbide. 

The  electric  arc  being  formed  in  the  furnace,  a  thoroughly 
incorporated  mixture  of  coke  and  lime  in  the  right  proportion  is 
introduced.  The  change  which  takes  place  is 

Ca  O  +  3  C  t=  Ca  C2  +  CO 

which  means  that  fifty-six  pounds  of  lime,  and  thirty-six  of  coke 
make  64  pounds  of  carbide,  and  liberate  twenty-eight  of  carbon 
monoxide,  a  gas  which  escapes  or  is  burned  at  the  mouth  of  the 
furnace.  Thus,  for  each  pound  of  carbide  made,  there  is  con- 
sumed a  pound  and  a  half  of  a  mixture  which  is  something  like 
seven-twelfths  lime  with  five-twelfths  coke. 

Granted  pure  material,  there  is  formed  an  ingot  of  very  pure 
carbide,  surrounded  by  a  crust  of  less  pure  product  because  par- 
tially unconverted. 

In  breaking  up,  packing  and  shipping  the  carbide,  this  poorer 
crust  is  rejected.  At  first  impure  materials  were  employed  for 
the  manufacture  of  carbide,  but  this  resulted  in  an  inferior  grade, 
which  in  turn  yielded  an  impure  gas,  so  that  at  the  present  time 
it  is  everywhere  recognized  as  essential,  that  only  first  class  ma- 
terials should  be  used. 

It  is  customary  to  use  lime  that  is  99  per  cent  pure,  and  coke 
of  low  ash.  Both  must  contain  as  little  sulphur  and  phosphorus  as 
possible. 

Carbide  decomposes  with  water  in  accordance  with  the  fol- 
lowing chemical  equation : 

Ca  C2  +  2  H2  O  =  C2  H2  +  Ca  (OH)2 
A  pound  of  absolutely  pure  carbide  will  yield   $l/2   feet  of 


CHKM1STRY  23 

acetylene,  but  absolute  purity  is  not  a  practical  commercial  possi- 
bility. In  practice  good  carbide  may  be  expected  to  produce 
never  less  than  four  cubic  ft.  and  rarely  more  than  five  cubic  ft. 
of  acetylene  gas  per  pound  of  carbide.  The  table  on  page  23  gives 
the  gas  yield  of  various  grades  carbide. 

TABLE  III. 

THE  AVERAGE  YIELD  OF  GAS. 
From  the  Various  Grades  of  Carbide. 

Grade  3%x2        4%  cubic  feet 

Grade  2     x  i/2    _.....4V2  cubic  feet 

Grade  li/U   %  «_4%  cubic  feet 

Grade     1/4xl/12    _.....4       cubic  feet 

Grade  Electrolite  _ 4       cubic  feet 

Calcium  Carbide  is  a  safe  substance  to  store  or  transport 
under  proper  conditions.  It  cannot  explode,  take  fire,  or  other- 
wise do  harm,  unless  exposed  to  moisture.  In  that  event  the 
water  in  the  moisture  will  slowly  liberate  acetylene  which  in  the 
presence  of  flame,  will  ignite. 

ACETYLENE. 

Acetylene  is  a  colorless,  tasteless  gas,  possessed  of  a  peculiar 
penetrating  odor.  It  is  a  compound  of  two  atoms  of  carbon  to  two 
atoms  of  hydrogen,  and  is  known  by  the  formula  C2  H2.  Being 
composed  of  these  two  elements  only,  it  belongs  to  a  class  of 
compounds  known  as  hydro-carbons.  All  hydro-carbons  are 
combustible  and  acetylene  will  explode  when  only  354  per  cent 
is  mixed  with  air.  Its  ignition  point  is  lower  than  coal  gas, 
being  about  900  degrees  F.  against  noo  degrees  required  to 
ignite  coal  gas.  It  burns  in  air  with  a  brilliant  but  smoky  flame, 
uniting  with  the  oxygen  of  the  air,  in  the  following  proportions. 

2  C2  H2  +  502  =  4  CO2  +  2  H2  O 

Acetylene  is  an  endothermic  compound.  In  its  formation 
heat  is  absorbed,  and  there  resides  in  the  acetylene  molecules  the 
power  of  spontaneously  decomposing  and  liberating  this  heat  if 
subjected  to  temperatures  or  pressure  beyond  the  capacity  of  its 


24  OXY-ACETYLENE    WELDING    AND    CUTTING 

unstaple  nature  to  withstand.  Acetylene  is  decomposed  into  its 
constituent  elements  at  a  critical  temperature  of  approximate!} 
1400  decrees  R,  or  at  the  critical  pressure  of  two  atmospheres 
(29.4  pounds)  at  which  pressure  it  becomes  dangerous. 

Acetylene,  without  the  mixture  of  air  or  oxygen,  at  ordinary 
pressures,  is  not  explosive  in  any  sense,  except  as  referred  to 
above. 

When  acetylene  is  used  in  the  blow  torch  it  combines  with 
oxygen  in  equal  volumes  and  liberates  much  heat.  The  tempera- 
ture of  the  oxy-acetylene  flame,  taken  at  the  extremity  of  the 
white  jet,  is  very  much  higher  than  that  of  any  other  flame.  It 
is  calculated  to  be  6300  degrees  F.  In  all  cases  the  white  jet  of 
the  oxy-acetylene  flame  can  melt  lime,  the  melting  point  of  which 
is  estimated  at  5432  degrees. 


CHAPTER  III. 

PHYSICS. 

Pneumatics. — Pneumatics  is  that  branch  of  mechanics  which 
treats  of  the  properties  of  gases  and  air. 

It  was  supposed  by  the  ancients  that  air  was  inponclerable, 
that  it  weighed  nothing,  and  it  was  not  until  the  year  1650  that 
it  was  proven  that  air  really  had  weight.  A  cubic  foot  of  air 
under  ordinary  conditions,  weighs  about  eight  one-hundredths 
of  a  pound.  Since  air  has  weight  it  is  evident  that  the  enormous 
quantity  of  air  that  constitutes  the  atmosphere  must  exert  con- 
siderable pressure  on  the  earth.  By  experiment  and  calculation 
this  pressure  has  been  determined  to  be  14.7  pounds  per  square 
inch. 

In  the  strictest  sense  of  the  word,  air  is  not  a  gas,  but  is  a 
mixture  of  gases  and  consists  of  about  23  parts  oxygen  and  77 
parts  nitrogen,  by  weight;  or  21  parts  oxygen  and  79  parts  nitro- 
gen, by  volume.  Its  physical  characteristics  are  the  same  as 
the  gases,  and  in  this  respect  it  is  classified  among  them. 

The  most  striking  feature  concerning  gases  is  that,  no  matter 
how  small  the  quantity  may  be  they  will  always  fill  the  vessels 
which  contain  them,  and  if  the  temperature  of  the  confined  gas 
remains  the  same,  the  pressure  and  volume  will  always  vary  the 
same  way.  The  law  which  expresses  this  is  called  Boyle's  Law, 
and  is  as  follows: 

Boyle's  Law. — The  temperature  remaining  constant  the  volume 
of  a  given  quantity  of  gas  varies  inversely  as  the  pressure. 

The  meaning  of  this  is :  If  the  size  of  the  containing  vessel  is 
diminished  to  y2  or  */J  of  its  former  volume,  the  pressure  of  the 
gas  will  be  increased  to  2  or  3  times  its  original  pressure.  It  also 
means  that  if  the  size  of  the  containing  vessel  is  increased  to  2 
or  3  times  its  original  volume,  the  pressure  will  diminish  to  */2 
or  T/3  of  the  former  pressure. 

In  these  and  the  following  statements  the  reader  should  not 
confuse  the  words  volume  and  quantity.  The  volume  will  corre- 
spond with  the  cubic  capacity  of  the  vessel,  while  the  quantity 
will  represent  the  amount  of  air  or  gas  contained  in  the  vessel 
under  pressure. 


26  OXY-ACETYLENE    WELDING    AND    CUTTING 

Suppose  a  steel  drum  is  such  a  size  that  it  will  measure  ex- 
actly 3  cubic  feet.  If  it  is  open  to  the  air  it  is  evident  the  drum 
will  contain  3  cubic  feet  of  air  at  atmospheric  pressure.  Then  if 
twice  as  much  air,  or  6  feet  is  put  into  the  drum,  the  pressure 
will  be  doubled  to  29.4  pounds,  and  if  one  hundred  times  as 
much  air  or  300  feet  is  put  into  the  drum  the  pressure  will  be 
raised  100  times  and  become  1470  pounds.  Now  if  half  of  this 
air,  or  150  feet,  is  drawn  out,  the  pressure  will  be  reduced  to  one- 
half  of  1470  pounds  and  become  735  pounds. 

As  a  necessary  consequence  of  Boyle's  law,  it  may  be  stated 
that,  the  quantity  of  gas  in  a  given  size  drum,  varies  directly  as 
the  pressure. 

Knowing  the  quantity  of  gas  a  drum  will  contain  under  cer- 
tain pressure,  the  quantity  for  any  other  pressure  may  be  calcu- 
lated by  the  following  simple  formula  in  which 

A  =  the  nominal  rated  pressure 

B  =  pressure  of  gas  in  drum 

C  =  capacity  of  drum  under  A  pressure 

X  =  contents  of  drum  in  cubic  feet  of  gas 

Then—  ^    =X 

Expressing  this  formula  in  words,  we  have  the  rule. 

Multiply  the  rated  capacity  of  the  drum  by  the  pressure  of 
gas  in  the  drum  and  divide  by  the  nominal  rated  pressure  to  find 
the  contents  of  the  drum. 

Suppose  an  oxygen  drum  contains  200  feet  of  gas  at  1800 
pounds  pressure,  and  after  being  used  for  sometime  the  pressure 
has  diminished  to  700  pounds.  If  we  wished  to  learn  the  quan- 
tity of  gas  still  remaining  in  the  drum,  the  calculation  would  be 
as  below. 

200  x  700  77 


In  all  that  has  been  said  before,  it  has  been  stated  that  the 


PHYSICS  27 

temperature  was  constant ;  the  reason  for  this  will  now  be  ex- 
plained. Suppose  a  definite  quantity  of  air  at  32  degrees  F.  be 
placed  in  a  cylinder  with  a  movable  piston  and  that  this  piston  is 
weighted  .to  cause  the  air  to  be  at  a  constant  uniform  pressure. 
If  the  temperature  of  the  air  within  the  cylinder  be  raised  to 
33  degrees  F.  it  will  be  found  that  the  piston  has  raised  a  cer- 
tain amount,  consequently  the  volume  has  increased  while  the 
pressure  remained  the  same.  If  more  heat  is  applied  and  the 
temperature  raised  to  34  degrees  F.  it  will  be  found  the  piston 
has  raised  again,  and  that  every  increase  in  temperature  will 
cause  a  corresponding  increase  in  volume.  The  law  that  expresses 
this  change  is  called  Gay-Lusac's  Law,  and  is  expressed  as  fol- 
lows: 

Gay  Lusac's  Laiv. — //  the  pressure  remains  constant  every 
increase  of  temperature  of  i  degree  F.  produces,  in  a  given 
quantity  of  gas,  an  expansion  of  4^2  of  its  volume  at  32  degrees 
F. 

If  the  pressure  remains  constant  it  will  be  found  that  every 
decrease  of  I  degree  F.  will  cause  a  decrease  of  ib  of  the  vol- 
ume at  32  degrees  F. 

According  to  the  modern  and  now  generally  accepted  theory 
of  heat,  the  atoms  and  molecules  of  all  bodies  are  in  an  incessant 
state  of  vibration.  The  vibratory  movement  in  gases  is  faster 
than  in  liquids,  and  in  liquids  it  is  faster  than  in  solids.  Any 
increase  in  heat  increases  the  vibrations,  and  a  decrease  in  heat 
decreases  them.  From  calculation  and  experiment,  it  has  been 
concluded  that  all  vibration  ceases  at  a  temperature  of  460  degrees 
below  zero.  This  point  is  called  absolute  zero,  and  all  tempera- 
tures reckoned  from  this  point  are  called  absolute  temperatures. 

When  the  word  temperature  alone  is  used  the  meaning  is  the 
same  as  ordinarily  applied,  but  when  absolute  temperature  is 
specified,  460  degrees  F.  must  be  added  to  the  temperature.  The 
absolute  temperature  corresponding  to  32  degrees  F.  is  460  + 
32  =  492  dgrees  F. 

In  calculating  the  effect  of  an  increasing  or  decreasing  tem- 
perature, upon  the  volume  or  pressure  of  gases,  the  temperature 
is  reckoned  from  absolute  zero. 


28  OXY-ACETYLENE    WELDING    AND    CUTTING 

Suppose  a  steel  drum  is  charged  with  200  cubic  feet  of  gas  at 
1800  pounds  pressure,  and  at  a  temperature  of  68  degrees  F. ; 
and  subsequently  the  temperature  is  raised  to  100  degrees  F.  The 
increase  in  pressure  may  be  calculated  by  the  following  formula 
in  which 

A  =  the  nominal  rated  pressure  of  the  drum  at  68  degrees 
Fahrenheit. 

T  =  the  absolute  temperature  of  68  degrees  F. 

t  =  absolute  temperature  of  gas  in  drums 
E  =  pressure  of  gas  at  t  temperature 

t 
Then A  =  E 


PHYSICS 


FIG.  12. 
HIGH  PRESSURE  PUMP  FOR  GAS  COMPRESSION. 

Three  cylinder  hydraulic  pump  having  capacity  to  compress  12  cubic 
feet  of  gas  per  minute  from  1,500  pounds  to  2,200  pounds  pressure  per 
square  inch. 


30  OXY-ACETYLENE    WELDING    AND    CUTTING 

Expressing  this  formula  in  words  we  have  the  rule.  Divide 
the  absolute  temperature  of  the  gas  in  the  drums  by  the  abso- 
lute temperature  of  68  degrees  F.}  and  multiply  the  quotient  by 
the  nominal  rated  pressure  of  the  drum,  to  find  the  pressure  due 
to  a  change  in  temperature. 

This  final  pressure  is  computed  as  shown. 
460  +   100  ==  560  _ 
460  -j-     68  ==  528 
1.06  x  1800  =  1908  =  final  pressure 

Heat. — As  to  the  exact  nature  of  heat,  scientists  differ,  but- 
all  modern  thinkers  and  investigators  agree  that  heat  is  a  form  of 
energy.  It  is  not  proposed  here  to  enter  into  the  different  theories 
regarding  heat,  but  this  much  of  the  generally  accepted  theory  is 
given  to  make  clear  the  principles  which  are  to  follow. 

To  avoid  possible  misunderstanding  the  attention  of  the  read- 
er is  first  directed  to  the  difference  between  the  quantity  and 
intensity  of  heat.  This  difference  is  easier  explained  by  a  series 
of  illustrative  statements. 

The  same  amount  or  quantity  of  heat  may  be  delivered  to 
equal  amounts  of  different  materials  without  having  the  same 
sensible  effect. 

Equal  weights  of  different  substances,  having  the  same  tem- 
perature may  be  placed  in  an  oven  and  be  subjected  to  the  same 
heat  for  the  same  length  of  time,  and  their  final  temperature  will 
be  considerably  different,  although  each  has  received  the  same 
quantity  of  heat. 

Then  it  is  clear  that  the  same  quantity  of  heat  will  not  raise 
the  same  weight  of  different  materials  to  the  same  temperature. 

Reversing  this  experiment  we  find  that  if  equal  weights  of  dif- 
ferent substances  be  heated  to  the  same  temperature  and  plunged 
into  vessels  containing  like  quantities  of  water  at  like  tempera- 
tures, the  water  in  the  different  vessels  will  not  be  raised  to  the 
same  degree  of  temperature. 

•  Then  it  is  clear  that  these  various  substances  actually  con- 
tained different  quantities  of  heat  at  the  same  temperature. 


PHYSICS  31 

Unit  of  Heat.  The  standard  with  which  quantities  of  heat  are 
measured  is  called  the  heat  unit,  and  represents  the  amount  of 
heat  required  to  raise  a  certain  amount  of  water  one  degree  in 
temperature.  Different  communities  use  the  same  general  meth- 
ods for  determining  heat  units,  but  vary  the  amount  of  water  to 
suit  the  convenience  of  their  national  standards,  therefore  it  was 
found  necessary  to  distinguish  between  the  methods  in  which 
different  standards  are  employed. 

The  British  Thermal  Unit. — The  quantity  of  heat  required  to 
raise  one  pound  of  water  one  degree  Fahrenheit,  is  called  a  British 
Thermal  Unit.  Instead  of  writing  out  the  words  British  Ther- 
mal unit  in  full  it  is  customary  to  abbreviate  them  B.  T.  U. 

The  Calorie. — The  quantity  of  heat  required  to  raise  one 
kilogram  of  ivater  one  degree  Centigrade  is  called  a  Calorie. 

One  calorie  is  equal  to  3.96  B.  T.  U. 

Temperature. — The  word  temperature  expresses  the  sensible 
heat  which  a  substance  possesses,  and  is  measured  by  comparison 
with  some  other  substance  having  the  same  amount  of  sensible 
heat.  For  convenience  and  for  scientific  purposes,  two  scales  ot 
comparison  are  employed.  Both  scales  are  compared  with  the 
same  substance  at  the  same  temperatures,  the  only  difference 
being  in  the  graduations  of  the  scales.  These  are  called  the 
Fahrenheit  and  Centigrade  scales. 

Thermometers. — The  instrument  on  which  these  compara- 
tive scales  are  arranged  to  measure  temperature  is  called  a  ther- 
mometer. The  divisions  of  the  scale  are  called  degrees,  the 
substance  with  which  they  are  compared  is  water,  and  the  tem- 
perature at  which  they  are  compared  is  the  freezing  point  and 
boiling  point. 

Fahrenheit.— On  the  Fahrenheit  scale  the  freezing  point  of 
water  is  marked  32,  and  the  boiling  point  212.  and  the  interven- 
ing space  divided  into  180  equal  parts  called  degrees.  Thirty- 
two  degrees  are  marked  off  on  the  lower  end  of  the  scale,  and 
called  zero.  So  in  speaking  of  water  we  would  say  that  it  freezes 
at  32  degrees  above  zero,  and  boils  at  212  degrees  above  zero. 


32  OXY-ACETYLEXE    WELDING    AND    CUTTING 

As  many  degrees  are  marked  above  the  boiling  point  or  below 
zero,  as  are  desired. 

Centigrade. — In  graduating  a  Centigrade  scale,  the  freezing 
point  is  marked  zero,  the  boiling  point  100,  and  the  intervening- 
space  is  divided  into  100  equal  degrees. 

It  will  be  observed  that  100  degrees  Centigrade  covers  the 
same  range  of  temperature  as  180  degrees  Fahrenheit,  therefore, 
one  degree  centigrade  equals  one  and  eight-tenths  degrees  Fah- 
heit. 

Temperatures  designated  by  one  scale  may  be  converted  to  the 
other  scale  by  formulas. 

When  F  =  degrees  Fahrenheit 
and  C      =  degrees   Centigrade 
Then  1.8  C  +  32  =  F. 

LT3L-C 
1.8 

Expansion. — The  volume  of  any  substance  is  always  changed 
when  the  temperature  is  changed ;  nearly  all  of  them  expand  when 
heated,  and  contract  when  cooled.  This  phenomenon!  causes  the 
welder  considerable  trouble  unless  it  is  thoroughly  understood, 
and  it  is  well  for  him  to  give  this  subject  much  thought  and  study, 
for  his  success  depends  to  a  great  extent,  on  his  ability  to  over- 
come the  effects  of  expansion  and  contraction.  The  method  of 
overcoming  these  effects  will  be  treated  fully  under  the  subject  of 
welding. 

Suppose  that  a  bar  of  iron  is  exactly  10  feet  long  at  a  tempera- 
ture of  50  degrees  F.,  if  the  temperature  be  raised  to  60  degrees  it 
will  be  found  that  it  has  lengthened  a  definite  amount.  If  the 
temperature  is  then  raised  to  70  degrees  it  will  be  found  to  have 
lengthened  exactly  the  same  amount  as  before.  This  is  true  of  all 
metals.  Each  metal  will  expand  a  certain  definite  amount  with 
every  degree  increase  in  temperature,  and  when  cooling  they  con- 
tract at  precisely  the  same  ratio ;  but  the  different  metals  do  not 
expand  with  the  same  ratio  as  compared  one  with  the  other. 


PHYSICS  33 

The  ratio  of  expansion  of  the  different  metals  has  been  deter- 
mined and  the  amount  of  expansion  of  one  inch  in  length  for  one 
degree  temperature  has  been  tabulated  into  a  table  called  coeffi- 
cients of  expansion.  These  seem  like  small  amounts,  but  when 
the  temperatures  are  high  the  amount  of  expansion  is  an  item  to  be 
considered. 

TABLE  V. 
COEFFICIENTS  OF  EXPANSION  FOR  VARIOUS  SUBSTANCES. 

Cast  Iron  .00000617 

Copper  00000955 

Brass  00001037 

Silver  00000690 

Bar  Iron  00000686 

Steel  (untemperp<l)  00000599 

Steel  (tempornl)  .00000702 

Aluminum  0000129 

Zinc  00001634 

Tin  00001410 

Mercury  .00003334 

Alcohol  00019259 

If  a  bar  of  cast  iron  48  in.  long  is  heated  from  50  degrees  F. 
to  a  bright  red,  or  1250  degrees  F,  the  amount  it  will  expand  may 
be  determined  by  formula  in  which, 

A  =  length  of  bar  in  inches 
B  =  the  raise  in  temperature 
C  =  coefficient  of  expansion 
D  =  amount  of  expansion  in  inches 
Then  A.  B.  C.  =  D. 
Expressing  this  formula  in  words  \ve  have  the  rule. 

Multiply  the  length  of  the  bar  in  inches  by  the  number  of  de- 
grees raise  in  temperature,  and  multiply  the  product  by  the 
coefficient  of  expansion,  to  find  the  amount  of  expansion  in 
inches.  The  coefficient  of  expansion  for  cast  iron  is  .0000x3617. 
Using  this  figure  and  multiplying  as  directed  we  find, 

48  x  1200  x  .00000617  =  .355392  or  Y*  of  an  inch. 

If  the  bar  mentioned  has  a  section  of  3  square  inches,  and 
forms  one  of  the  arms  in  a  gear,  with  one  end  attached  to  the  hub 
and  the  other  end  in  the  rim,  it  will,  when  heated,  exert  a  thrust  of 


34  OXY-ACETLYENE    WELDING    AND    CUTTING 

135  tons  against  the  rim.  It  is  useless  to  try  to  resist  this  enor- 
mous pressure,  and  the  only  way  to  avoid  trouble  is  to  heat  other 
portions  of  the  gear  so  that  all  parts  will  expand  together.  In 
the  parlance  of  the  welder,  this  method  is  called  preheating. 

Expansion  extends  in  all  directions.  If  a  steel  plate  four  feet 
square  is  heated  red  hot  it  will  become  3A  of  an  inch  wider,  and 
M  of  an  inch  longer ;  and  when  it  cools  it  will  contract  the  same 
amount.  If  the  edges  are  welded  solid  while  the  plate  is  hot.  the 
strain  caused  by  contraction  will  amount  to  many  tons. 

The  amount  of  the  expansion  depends  on  the  temperature,  and 
extent  of  the  heated  portion.  If  a  bar  of  metal  is  heated  in  the 
center,  the  heat  will  be  greatest  at  the  point  where  the  heat  is 
applied.  Some  of  this  heat  will  be  conducted  through  the  bar, 
and  some  will  radiate  to  the  air.  The  distance  to  which  it  will  be 
conducted  through  the  bar  depends  on  the  speed  at  which  the 
bar  will  conduct  it  as  compared  with  the  rate  of  radiation. 

If  bars  of  different  metals  are  heated  in  the  center  the  distance 
to  which  the  heat  will  travel  in  the  various  bars  will  be  greatest  in 
the  metals  that  are  the  best  conductors,  and  since  the  extent  of 
the  heated  portion  is  one  of  the  determining  factors  of  expansion 
it  follows,,  When  bars  of  different  metals  have  heat  applied  to  a 
limited  section,  the  best  conductors  will  be  expanded  most,  if 
other  factors  are  equal. 

Silver  stands  foremost  among  the  metals  as  a  conductor  of 
heat.  Representing  the  conductivity  of  silver  by  100  the  follow- 
ing table  shows  the  conducting  power  of  some  of  the  metals. 

TABLE  IV. 
HEAT  CONDUCTIVITY  OF  DIFFERENT  METALS. 

Silver  „ 100.00  Iron 11.9 

Copper  :....  73.6  Steel  11.6 

Gold  53.2  Lead  8.5 

Aluminum  31.3  Platinum  8.4 

Brass , 23.1  Rose 's  Alloy 2.8 

Zinc    19.0  Bismuth  ".. 1.8 

Tin   ...  14.5 


35 

CHAPTER  IV. 

METALS  AND  THEIR  PROPERTIES. 

The  Ferrous  Group. — Pure  iron  is  a  white  metal  and  one  of 
the  chemical  elements,  and  although  it  is  with  one  exception  the 
commonest  and  most  abundant  metal  in  the  earth  it  never  occurs 
in  nature  in  the  pure  metallic  form,  but  is  always  united  with 
oxygen,  neither  does  it  exist  as  an  article  of  commerce,  but 
appears  on  the  market  contaminated  with  carbon,  silicon,  and  other 
impurities  forming  cast  iron,  wrought  iron,  or  steel.  These 
three  products  comprise  the  ferrous  group,  and  are  the  largest 
manufactured  product  in  the  world. 

Iron  has  a  chemical  affinity  for  oxygen  and  carbon.  The 
former  element  is  ruinous  and  destructive,  but  the  latter  element 
gives  it  greater  strength  and  at  the  same  time  makes  it  harder 
and  more  brittle.  So  important  is  the  influence  of  carbon  in 
controlling  the  characteristics  of  the  ferrous  metals,  that  they 
are  classified  according  to  the  amount  of  carbon  in  them.  When 
melted  in  the  presence  of  these  elements  it  combines  with  them 
very  rapidly,  and  their  effect  on  the  metal  should  be  constantly 
borne  in  mind  when  we  are  using  an  oxy-acetylene  torch,  for  an 
excess  of  either  oxygen  or  acetylene  gas  will  contribute  oxy- 
gen or  carbon  to  the  melted  metal. 

Cast  Iron. — Cast  iron  is  the  most  impure  of  the  ferrous  prod- 
ucts, and  in  consequence  it  is  comparatively  weaker,  more  brittle 
and  melts  at  a  lower  temperature  than  wrought  iron  or  steel. 
A  typical  example  of  cast  iron  would  contain  about  931/2  per 
cent  pure  iron,  3^2  per  cent  carbon  and  3  per  cent  other  impuri- 
ties. Its  tensile  strength  would  be  about  23000  pounds,  and  its 
melting  point  about  2200  degrees  Fahrenheit.  In  solidifying 
from  the  molten  condition  to  the  temperature  of  the  air  it  shrinks 
or  shortens  about  one-eighth  of  an  inch  to  every  foot  in  length, 
or  when  in  the  solid  state  it  shrinks  about  one  sixty- fourth  of 
an  inch  for  every  200  degrees  decrease  in  temperature.  This 
feature  requires  the  serious  consideration  of  the  welder,  for 
when  cast  iron  is  solidifying  it  is  in  its  very  weakest  state,  and 
unless  this  shrinkage  or  contraction  is  provided  for,  cracks  will 
ensue. 


36  OX Y- ACETYLENE    WELDING    AND    CUTTING 

Another  feature  which  may  cause  trouble  to  the  welder,  is 
the  transfer  of  carbon  from  the  graphite  to  the  combined  form 
by  rapid  cooling  from  the  molten  condition. 

Carbon  is  contained  in  solidified  cast  iron  in  two  forms,  the 
graphitic  form  in  which  free  carbon  is  mechanically  mixed 
with  the  iron  in  little  flakes  of  graphite ;  and  the  combined  form, 
in  which  the  carbon  is  chemically  united  with  the  iron.  In  the 
graphitic  form  it  does  not  effect  the  hardness  of  iron,  but  in 
the  combined  form  it  will  cause  the  iron  to  be  hard  or  soft 
according  to  the  amount  contained  in  it. 

The  welder  should  remember  that  carbon  is  always  in  the 
combined  state  with  iron  when  the  mass  is  in  a  molten  condition, 
and  as  it  cools  graphite  precipitates,  but  this  cooling  must  be 
very  slow  for  the  change  to  take  place  since  it  is  a  very  sluggish 
change  and  requires  several  seconds  for  its  accomplishment; 
but  on  the  contrary  if  the  mass  is  cooled  rapidly  this  precipita- 
tion of  graphite  is  prevented  and  a  metal  is  obtained  in  which  all 
the  carbon  is  in  the  combined  form,  producing  an  iron  that  may 
be  as  brittle  as  glass  and  so  hard  that  it  cannot  be  machined  or 
filed.  This  rapid  cooling,  which  is  called  chilling,  may  be  accom- 
plished by  dropping  the  melted  iron  on  to  a  cold  metal  surface, 
and  the  resultant  hard  cast  iron  is  called  chilled  iron. 

Malleable  Cast  Iron  is  first  cast  in  the  condition  of  very  hard, 
brittle  white  cast  iron.  It  has  less  carbon  and  silicon  in  its 
composition  than  other  cast  iron,  and  when  poured  in  the  moulds 
which  give  it  the  desired  shape  it  is  rapidly  cooled  so  that  nearly 
all  the  carbon  it  contains  is  in  the  combined  form.  It  can  be 
readily  understood  from  the  preceding  paragraph  that  if  this 
combined  carbon  can  be  precipitated  to  graphite  the  casting  will 
be  softer,  and  furthermore  if  the  size  of  these  flakes  of  graphite 
can  be  reduced  the  casting  will  be  stronger  because  the  smaller 
are  the  planes  of  easy  rupture.  Being  softer  and  stronger  it  may 
be  bent  and  is  called  malleable. 

Eliminating  and  changing  the  carbon  in  white  cast  iron  to 
make  it  malleable  is  accomplished  by  prolonged  heat  treatment 
and  the  process,  which  is  called  annealing,  is  performed  after 
the  iron  has  been  cast  into  moulds  and  cooled.  Thev  are  then 


MKTALS    AND    THEIR    PROPERTIES  37 

cleaned  and  packed  in  iron  boxes  with  some  pulverized  sub- 
stance containing  oxide  of  iron,  such  as  iron  ore,  or  mill  scale, 
placed  in  an  annealing  furnace  and  heated  to  a  temperature  of 
1300  degrees,  and  at  this  temperature  they  are  kept  for  many 
hours.  While  under  this  heat  there  occurs  the  precipitation  of 
graphite,  which  normally  would  have  occurred  during  solidifi- 
cation, and  in  the  majority  of  cases  nearly  all  of  the  combined 
carbon  is  changed  to  graphite,  or  eliminated  by  uniting  with 
the  oxygen  in  the  material  used  for  packing. 

Under  this  treatment  the  graphite  does  not  form  in  flakes 
vis  in  ordinary  cast  iron,  but  forms  in  minute  particles  which  are 
not  nearly  so  weakening  or  embrittling  to  the  casting  as  flakes 
of  graphite  would  be.  The  whole  annealing  process  requires 
about  six  days  of  continuous  firing,  and  should  not  be  attempted 
by  persons  who  are  not  familiar  with  the  chemistry  of  iron,  or 
who  do  not  possess  an  equipment  of  furnace,  iron  packing  boxes 
and  packing. 

Since  malleable  iron  is  always  cast  in  the  form  of  hard  white 
iron  and  subsequently  made  malleable  by  a  process  applied  to  its 
exterior,  it  follows  that  the  change  of  structure  is  more  com- 
plete at  the  surface  giving  the  outside  the  texture  of  mild  steel, 
while  the  middle  portion  may  resemble  a  very  soft  cast  iron. 
It  is  this  peculiarity  which  frustrates  the  efforts  of  the  amateur 
welder. 

Wrought  Iron. — Wrought  iron  is  almost  the  same  as  very 
low  carbon  steel,  its  chief  distinction  being  in  the  method  of 
refining  rather  than  the  composition  of  the  metal.  It  is  made 
by  melting  pig  iron,  steel  scrap  and  other  ferrous  materials  in 
contact  with  iron  ore,  and  burning  out  the  impurities,  leaving 
metallic  iron.  This  iron  is  not  in  a  melted  state  when  finished, 
for  the  temperature  of  the  furnace  is  not  sufficiently  high  to 
keep  it  fluid  after  the  carbon  has  been  burned.  It  is  in  a  pasty 
condition  and  when  taken  out  of  the  furnace  is  a  honey-comb  of 
iron  with  each  cell  filled  with  melted  lava.  This  honey-comb  is 
then  squeezed  and  rolled  until  most  of  the  slag  is  worked  out 
and  the  iron  frame  work  welded  together  in  a  crude  rough  bar. 
These  bars,  which  are  an  intermediate  product,  called  "muck 


38  OXY-ACETYLENE    WELDING    AND    CUTTING 

bars",  are  then  cut  into  lengths,  "piled",  heated  to  a  welding 
heat  and  rolled  again,  and  after  this  second  rolling  they  become 
the  "merchant  iron"  of  commerce. 

The  finished  bar  contains  less  than  .12  per  cent  carbon  and 
about  1.5  per  cent  slag.  Some  think  that  this  slag  serves  as  a 
flux  and  assists  in  welding,  but  this  is  doubtful.  It  is  more 
probable  that  the  easy  welding  of  wrought  iron  is  due  alone  to 
its  being  low  in  carbon. 

Steel — In  olden  times  all  kinds  of  steel,  whether  made  in  the 
crucible,  in  the  cementation  chamber  or  in  the  puddle  furnace, 
contained  carbon  enough  to  make  them  suitable  for  cutting  tools 
when  hardened  in  water,  and  the  steels  that  were  later  made  in 
the  Bessemer  converter  during  the  early  days  of  its  history  were 
all  more  or  less  hard,  much  of  it  being  used  for  tools ;  conse- 
quently the  metal  made  in  the  converter  was  called  Bessemer 
steel. 

As  time  went  on  and  the  cost  of  operation  was  reduced  below 
that  of  making  wrought  iron,  a  great  deal  of  very  soft  metal 
was  made  in  the  converter  and  open-hearth  furnace.  It  was 
impossible  to  draw  the  line  between  this  steel  and  the  earliest 
products  of  the  converter,  so  practical  men  in  America  and 
Europe  did  not  try  to  do  so,  but  called  everything  that  was  made 
in  the  converter,  or  in  the  open-hearth,  or  in  the  crucible  by  the 
name  of  stetel,  although  the  product  may  at  times  resemble 
wrought  iron,  and  it  is  a  fact  that  the  method  by  which  steel  is 
made  cannot  be  discovered  by  ordinary  chemical  analysis. 

The  primitive  Tubal  Cain  could  produce  a  hard  cutting  instru 
ment  with  no  apparatus  save  a  wrought  iron  bar  and  a  pile  of 
charcoal;  and  the  natural  developments  have  led  to  the  conclu- 
sion that  a  given  content  of  carbon  will  confer  a  greater  hard- 
ness and  strength,  with  less  accompanying  brittleness  than  any 
other  element. 

There  is  such  a  widely  varying  quantity  of  carbon  and  other 
alloys  in  steel,  accompanied  by  as  wide  a  range  of  physical 
properties,  that  the  subject  cannot  be  treated  in  a  book  of  this 
kind ;  but  before  leaving  the  subject  it  is  well  to  speak  of  a  proc- 


METALS    AM)    Til  KIR    PROPERTIES 


ess  by  which  hard  tool  steel  may  be  made,  which  has  not  here- 
tofore been  mentioned.  This  is  known  as  the  "cementation" 
or  "blister"  process  and  is  undoubtedly  the  one  used  by  Tubal 
Cain  as  mentioned  in  the  preceding  paragraph.  Blister  steel  is 
made  by  placing  bars  of  very  pure  iron  in  long  pots  with  char- 
coal and  exposing  them  to  about  1300  degrees  heat.  This  heat 
is  maintained  for  about  ten  days  and  when  the  bars  are  removed 
they  are  graded  according  to  their  carbon  content  which  ranges 
from  .5  to  1.5  per  cent.  Although  this  process  is  expensive,  it 
produces  a  very  fine  grade  steel  and  it  is  still  being  used  in 
Sheffield,  England. 

This  process  is  mentioned  here  to  remind  the  welder,  that  un- 
less he  uses  a  perfectly  neutral  flame,  it  is  possible  to  carbonize 
his  weld,  and  form  a  scale  that  cannot  be  machined.  In  other 
words,  if  he  uses  more  acetylene  gas  than  his  oxygen  can 
consume,  the  carbon  of  the  unburned  acetylene  may  unite  with 
the  iron  by  a  process  somewhat  similar  to  the  blister  process. 

Like  other  metals  steel  expands  and  contracts  with  heat  or 
cold,  and  the  amount  of  this  expansion  is  about  one  sixty-fourth 
of  an  inch  for  every  250  degrees  change  of  temperature. 

TABLE  VI. 
MELTING  TEMERATUKE  OF  METALS. 


Name  of  Metal 

Temperature 

Name  of  Metal 

Temperature 

C        |       P 

C 

F 

Tin  

223 
327 
419 
657 
900 
950 
961 
1065 
1065 

449 
621 
786 
1212 
1652 
1742 
1762 
1949 
1949 

White  Cast  Iron 
Gray  Cast  Iron... 
Hard  Steel  
Mild  Steel  . 

1100 
1200 
1400 
1471 
1484 
1500 
1776 
2000 

2012 
2192 
2552 
2680 
2703 
2730 
3232 
3632 

Lead  
Zinc 

Aluminum 

Bronze  
Brass  
Silver  
Copper  
Gold  

Nickel  
Wrought  Iron  ... 
Platinum  
Iridium  

COPPER. 

Copper  is  the  only  metal  which  occurs  free  in  large,  widely 
distributed  deposits.  For  this  reason,  it  was  the  first  metal 
exclusively  used  by  man.  The  copper  age  followed  the  stone 
age.  The  island  of  Cyprus  was  noted  in  the  time  of  the  Romans 


40  OX Y- ACETYLENE    WELDING    AND    CUTTING 

for  its  production  of  copper,  or  as  it  was  then  called,  Cyprian 
brass. 

\Ye  obtain  the  symbol  Cu.  from  the  Latin  name.  Cuprum. 

The  noted  mines  of  native  copper  in  Michigan,  along  the 
south  shore  of  Lake  Superior,  were  extensively  worked  before 
Columbus  discovered  America. 

From  them  masses  of  copper  of  enormous  size,  one  of  which 
weighed  nearly  five  hundred  tons,  have  been  obtained.  These 
mines  are  still  an  important  source  of  copper. 

Copper  has  a  characteristic  reddish  color.  Only  two  of  the 
common  metals,  gold  and  silver,  surpass  it  in  malleability  and 
ductility,  and  it  stands  next  to  silver  in  as  a  conductor  of  elec- 
tricity and  heat. 

The  tensile  strength,  which  is  about  33,000  Ibs.  per  square 
inch  at  ordinary  temperatures,  decreases  rapidly  under  the  effect 
of  heat.  At  932  degrees  it  is  only  about  14000  Ibs.  per  square 
inch.  When  copper  is  melted  it  oxidizes  rapidly  in  contact  with 
air,  and  this  oxide  is  very  soluble  in  the  metal;  it  forms  with  it 
an  alloy,  which  crystallizes  with  the  mass  on  cooling.  Melted 
copper  also  absorbs  hydrogen  and  carbon  monoxide  which  are 
present  in  the  oxy-acetylene  flame,  and  on  cooling,  the  metal  is 
riddled  with  blow  holes.  The  effect  of  this  oxidation  and  absorb- 
tion  of  gases,  can  only  be  overcome  by  the  use  of  fluxes  and 
alloys  in  the  welding  rod. 

BRASS. 

Brasses  are  alloys  of  copper  and  zinc.  They  do  not  conduct 
heat  so  readily  as  copper,  but  their  tensile  strength  when  hot  is 
much  higher  than  copper.  The  reader  will  note  the  great  dif- 
ference in  melting  points  in  the  two  principal  elements  in  brass. 
Zinc  melts  at  786  degrees  F.  and  vaporizes  at  1684  degrees, 
while  the  melting  point  of  copper  is  1949  degrees,  or  265  degrees 
higher  than  the  vaporization  temperature  of  zinc.  When  brass 
is  melted  under  the  direct  action  of  the  flame,  this  vaporization 
of^zinc  is  very  pronounced.  The  copper  in  brass  also  retains 
its  property  of  absorbtion  and  oxidation.  So  we  say  that  the 


MKTALS    AND    THEIK    I'KOl'KRTI  KS  41 

melting  of  brass  under  the  action  of  the  torch  is  attended  by 
three  distinct  phenomena :  Absorbtion  of  gases :  volatilization 
of  zinc;  and  oxidation. 

These  difficulties  are  overcome  by  use  of  the  proper  welding 
rods. 

ALLOYS. 

*  According  to  the  authoritive  definition,  "a  metalic  alloy  is  a 
substance  possessing  the  general  physical  properties  of  a  metal, 
but  consisting  of  two  or  more  metals,  or  of  metals  with  non- 
metallic  bodies,  in  intimate  mixture,  solution,  or  combination, 
forming  when  melted,  a  homogeneous  fluid. 

In  plain  language,  this  means  that,  when  melted,  the  dif- 
ferent components  are  dissolved  in  one  another.  Metal  alloys 
therefore,  come  under  the  general  heading  of  solutions.  In  fact 
the  great  bulk  of  our  alloys,  are  produced  by  first  dissolving 
the  melted  components  and  then  allowing  them  to  freeze.  The 
law  governing  this  freezing,  or  solidification,  have  only  been 
known  a  few  years,  and  this  new  knowledge  has  made  great 
revolution  in  physical  chemistry. 

In  perfect  alloys,  the  solid  solution  bears  the  same  relation 
to  the  melted  solution  as  a  pure  solid  metal  does  to  the  same 
metal  when  melted.  Consequently  any  solution  of  these  metals 
will  cool  to  the  freezing  point,  without  there  being  any  impor- 
tant change  in  their  relation. 

The  reason  that  these  solid  solutions  form  in  any  proportion 
is  that  the  two  metals  crystallize  alike.  It  is,  perhaps,  a  new 
thought  to  the  reader,  but  it  is  true,  that  a  metal  forms  a  crystal 
when  it  solidifies.  Furthermore,  each  metal  has  a  particular, 
general  shape  which  its  crystals  assume,  and  there  is  no  force 
powerful  enough  to  prevent  them  from  taking  this  shape  in 
preference  to  any  other. 

Tiny  as  the  crystals  sometimes  are,  often  requiring  the  highest 
powers  of  the  microscope  to  reveal  them,  their  crystalline  forces 
are  very  powerful.  If,  therefore,  two  metals  do  not  form  like 
crystals,  they  cannot  solidify  in  solution,  i.  e.,  in  the  same  crystal, 

*From  Metallurgy  of  Iron  and  Steel,  by  Bradley  Stoughton. 


42  OXY-ACETYLENE  WELDING  AND  CUTTING 

but  crystallization    (i.   e.,   freezing-)    must    be    accomplished    by 
precipitation,  or  separation  into  two  distinct  substances/' 

There  are  a  great  number  of  alloys  all  having  different  phys- 
ical properties,  and  this  difference  is  sometimes  due  to  the 
presence  of  an  element  in  very  small  proportions.  When  melted 
the  components  of  an  alloy  sometimes  react  with  the  flame  in 
entirely  different  ways,  and  unless  welding  rods  and  fluxes  are 
used,  which  will  compensate  for  this  reaction,  the  entire  struc- 
ture of  the  alloy  may  become  changed.  The  welder  should 
therefore  carefully  adhere  to  the  instructions  given  on  welding 
the  various  alloys. 

On  the  following  page  is  givei  a  list  of  alloys,  their  compo- 
sition and  proportions. 

Sb.  —  Antimony,  Bi  =  Bismuth,  Cu.  =  Copper,  Au.  =  Gold, 
Fe.  =  Iron,  Pb.  =  Lead,  Ni.  =Nickle,  Ag.  =  Silver,  Su.  =  Tin, 
Zn.  =  Zinc. 

TABLE  OF  ALLOYS. 

Name  of  Alloy.  Proportion  by  weight. 

Brass,  common  yellow 2  Cu,  1  Zn 

Brass,  to  be  rolled 32  Cu,  10  Zn,  1.5  Su 

Brass  castings,  common  20  Cu,  1.25  Zn,  2.5  Su 

Brass  castings,  hard  25  Cu,  2  Zn,  "4.5  Su 

Brass,   propellers  8  Cu,  .5  Zn,  1  Su 

Gun  metal 8  Cu,  1  Su 

Copper  flanges 9  Cu,  1  Zn,  .26  Su 

Statuary  91.4  Cu,  5.53  Zn,  1.7  Su,  1.37  Pb 

German  Silver 2  Cu,  7.9  Ni,  6.3  Zn,  6.5  Fe 

Britannia 50  Sb,  25  Su,  25  Bi 

Chinese  Silver 65.1  Cu,  19.3  Zn,  13  Ni,  2.58  Ag,  12  Fe 

Chinese  white  copper 20.2  Cu,  12.7  Zn,  1.3  Su,  15.8  Ni 

Medals 100  Cu,  8  Zn 

Babbitt's  metal 25  Su,  2  Sh,  .5  Cu 

Bell  metal,  large  _ 3  Cu,  1  Su 

Bell  metal,  small  ...4  Cu,  1  Su 

Chinese  Gongs 40.5  Cu,  9.2  Su 

Telescope  mirrors 33.3  Cu,  16.7  Su 

White  metal,  ordinary 3.7  Cu,  3.7  Zn,  14.2  Su,  28.4  Sb 

White  metal,  hard 35  Cu,  13  Zn,  2.2  Su 

Metal,  expands  in  cooling 75  Pb,  16.7  Sb,  8.3  Bi 


METALS   AND   THEIR   PROPERTIES  4:t 

ALUMINUM. 

Although  aluminum  is  one  of  the  most  abundant  and  widely 
distributed  metals,  it  never  occurs  free  in  nature.  Our  common 
clay  consists  chiefly  of  aluminum  silicate  and  it  has  been  esti- 
mated, there  is  enough  aluminum  in  every  brick  to  form  a  coat- 
ing an  eighth  of  an  inch  thick,  over  its  surface.  Therefore  it  is 
not  the  scarcity  of  aluminum  that  contributes  to  its  cost ;  but  the 
expense  of  extracting  it  from  the  silicate. 

The  only  process  used  at  present  for  the  extraction  of  alum- 
inum is  an  electrolytic  one.  The  apparatus  consists  of  a  rec- 
tangular iron  box,  lined  with  a  thick  layer  of  carbon  which  con- 
stitutes the  cathode.  The  inskle  dimensions  are  about  41/2  feet 
long,  2]/2  feet  wide,  and  6  inches  deep.  Carbon  rods  about  3, 
inches  in  diameter  and  18  inches  long,  placed  in  rows  and  sup- 
ported by  copper  bars,  serve  as  the  anodes.  The  process  is 
made  continuous  by  adding  raw  material  at  the  top  and  draw- 
ing off  the  aluminum  at  the  bottom.  The  product  is  99  to  99^/2- 
per  cent  pure,  and  the  remaining  y2  per  cent  impurities  con- 
sists of  traces  of  iron,,  silicon  and  sodium.  Aluminum  melts 
at  1 21 2  degrees  F.,  and  when  in  the  molten  state  it  oxidizes 
rapidly  and  absorbs  gases. 

The  strong  affinity  of  aluminum  for  oxygen  is  made  use  of 
in  the  product  called  Thermite. 

Thermite. — When  a  mixture  of  very  fine  particles  of  alum- 
inum and  iron  oxide  (iron  rust)  is  ignited  a  rapid  combustion 
and  very  high  temperature  ensues.  In  this  reaction  the  oxygen, 
in  the  iron  oxide,  unites  with  the  aluminum,  setting  the  iron 
free  and  liberating  4400  degrees  heat.  This  mixture  of  aluminum 
and  iron  oxide  is  known  by  the  trade  name  of  Thermite,  and 
the  reaction  of  this  substance  is  used  to  furnish  heat  and  material 
for  thermite  welding. 


44  OX Y- ACETYLENE    WELDING    AND    CUTTING 

CHAPTER  V. 
ACETYLENE  GENERATORS. 

The  function  of  an  acetylene  generator,  is  in  principle,  a 
simple  one.  It  has  to  bring  together  the  water  and  carbide, 
wash  the  gas  and  store  it  in  such  quantities  as  may  be  neces- 
sary. There  are  two  general  methods  of  bringing  the  water 
and  carbide  together,  viz.,  "carbide  to  water"  and  "water  to 
carbide."  Generators  are  therefore  more  frequently  designated 
as  carbide- feed,  and  water  feed,  respectively.  Inasmuch  as  it 
is  easier  to  regulate  the  flow  of  water,  by  means  of  valves  and 
other  methods  in  common  use.  than  to  control  the  distribution 
of  carbide,  it  was  natural  that  the  earlier  generators  should 
operate  by  sprinkling,  or  dripping  water  onto  the  carbide.  Later, 
it  was  observed  that  the  more  rational  plan  was  to  drop  suit- 
able quantities  of  carbide  into  a  large  excess  of  water.  From 
these  principles  originated  the  various  types  of  generators  which 
are  on  the  market  today. 

Recall  the  heating  phenomena  of  reaction.  Water  consists 
of  hydrogen  and  oxygen,  the  dissociation  of  which  absorbs  heat. 
On  the  other  hand,  the  oxygen  liberated  combines  with  the  cal- 
cium carbide,  and  the  reaction  liberates  much  more  heat  than  is 
absorbed  by  the  former  reaction.  This  excess  of  heat  is  about 
900  B.  T.  U.  per  pound  of  carbide;  which  is  sufficient  to  raise 
the  temperature  of  one  gallon  of  water  through  90  degrees  F. 
No  device  or  arrangement  can  alter  the  amount  of  heat  liberated, 
and  if  no  cooling  is  effected,  and  the  carbide  is  in  excess  pro- 
portion to  the  water,  the  temperature  may  become  very  high. 
High  temperatures  may  be  caused  when  large  quantities  of  car- 
bide are  heaped  in  a  quantity  of  water.  In  the  exterior  of  this 
heap  the  water  reacts  with  the  carbide  rapidly  and  the  heat 
liberated  prevents  it  reaching  the  interior  of  the  mass,  except 
in  very  small  quantities.  Around  the  outside  the  carbide  is 
decomposed  to  lime,  and  lime  being  a  poor  conductor,  prevents 
the  radiation  of  the  heat  liberated  at  the  interior.  Under  these 
conditions  the  mixture  may  become  red  hot. 

Although,  as  has  been  said  before,  no  arrangement  can  alter 
the  amount  of  heat  liberated,  the  temperature  may  be  regulated 


ACKTYLKNK  GENERATORS  4r, 

by  having-  an  excess  of  water  to  absorb  the  heat.  Regardless  of 
this  there  are  generators  manufactured  which  do  not  utilize  this 
or  any  other  cooling  agency. 

Drip  Type  Generator. — In  this  type  of  generator,  small  quan- 
tities of  water  are  dropped  onto  a  large  mass  of  carbide.  The 
amount  of  water  being  regulated  by  the  pressure  or  quantity  of 
the  accumulated  gas.  On  account  of  their  simplicity  they  are 
frequently  used  for  small  portable  generators,  and  when  started 
they  should  be  allowed  to  work  continuously  until  the  supply 
of  carbide  is  exhausted.  These  generators  give  the  greatest 
amount  of  heating  and  the  most  impure  gas. 

Flooding  Type  Generators. — In  this  generator  the  carbide 
is  placed  in  pans,  having  dividing  walls  to  separate  them  into 
compartments  containing  about  two  pounds  each.  The  water 
control  is  arranged  to  first  enter  compartment  No.  i,  exhausts 
and  completely  floods  it,  and  then  flows  into  the  next  compart- 
ment where  it  finds  a  fresh  supply  of  carbide.  This  overflowing 
from  one  compartment  to  the  other,  continues  until  the  contents 
of  the  generator  are  exhausted.  These  generators  possess  the 
same  disadvantages  as  the  drip  type;  but  not  to  so  marked  a 
degree. 

Carbide  to  Water  Type. — These  generators  are  provided  with 
a  hopper  of  some  sort,  which  contains  the  carbide,  and  are  pro- 
vided with  a  mechanism  for  automatically  dropping  it  into  the 
water  below,  at  the  right  time  and  measured  quantities  to  main- 
tain a  constantly  uniform  pressure.  These  feeding  mechanisms 
are  of  two  kinds,  one  consists  of  some  kind  of  a  valve  or  shutter 
which  opens  at  the  right  moment  and  drops  the  carbide  directly 
into  the  water,  the  other  depends  on  feeding  the  carbide  over 
the  edge  of  the  plate.  Either  of  these  arrangements  must  be 
safeguarded  so  that  it  is  impossible  to  accidently  drop  the  entire 
quantity  of  carbide  into  the  water. 

The  feeding  mechanism  must  be  positive,  strong  and  simple, 
for  on  it  depends  the  perfect,  uninterrupted  and  economical 
operation  of  the  machine.  It  must  positively  feed  carbide  when 
it  is  needed,  and  with  equal  reliability  prevent  the  feeding  of 


OXY-ACETYLENE    WELDING    AND    CUTTING 


FIG.  14. 
TYPICAL,  CARBIDE  TO  WATER  GENERATOR. 


AC  KT  Y  L E N  K  G  K  N  K  K  A  T( )  It  S  47 

carbide  when  it  is  not  needed.  The  water  chamber  should  hold 
enough  water  to  absorb  the  heat  liberated  by  the  decomposing 
carbide,  without  excessive  temperature,  and  the  carbide  should 
be  fed  in  very  small  quantities  (piece  by  piece)  with  diminishing 
or  increasing  frequency  as  the  demand  for  gas  decreases  or 
increases. 

When  standing  in  the  shop,  acetylene  generators  are  subject 
to  accidents  and  mishaps,  just  the  same  as  any  other  piece  of 
equipment;  the  tang  of  a  file  may  be  thrown  through  the  shell 
of  the  generator  and  allow  the  gas  to  escape.  To  avoid  trouble  in 
instances  of  this  nature,  the  modern  generators  provide  that 
carbide  will  not  feed  into  the  water  in  consequence  of  lowered 
pressure  due  to  accidents  to  the  generator.  This  is  accomplished 
by  utilizing  the  flow  of  gas,  to  the  service  pipe,  to  operate  the 
carbide  feed. 

"Carbide  to  water"  generators  as  just  described,  generate 
the  most  pure,  cool,  gas  at  a  constantly  uniform  pressure.  They 
are  more  economical,  safer,  and  otherwise  more  satisfactory  than 
either  the  Drip  Type  or  Flooding  Type  generators. 

There  are  two  different  designs  in  this  type  of  generator. 
One  having  a  gasometer  in  which  a  quantity  of  gas  is  stored 
ready  for  instant  use;  and  the  other  in  which  no  gasometer  is 
required,  the  gas  being  generated  on  demand.  Generators  with- 
out gasometers  have  the  advantage  of  having  less  gas  in  storage 
in  case  of  injury  from  accidental  causes;  they  are  less  liable  to 
give  trouble  by  freezing,  they  are  not  so  cumbersome  to  handle 
and  consequently  better  adapted  to  portable  use. 

Selecting  a  Generator. — As  to  the  selection  of  a  generator, 
there  are  good  generators  in  both  of  the  last  named  types,  and 
it  is  an  easy  matter  to  select  the  one  best  suited  to  your  require- 
ments. Of  whatever  type  it  may  be,  a  good  generator  should 
possess  the  following  qualities : 

(i)  It  must  insure  cool  generation.  Since  all  machines 
are  slightly  heated  during  rapid  generation,  a  pound  of  carbide 
decomposed  in  water  always  liberates  the  same  amount  of  heat. 
Nine  hundred  B.  T.  U's.  are  liberated  from  every  pound  of 


48  OXY-ACETYLENE    WELDING    AND    CUTTING 

decomposed  carbide,  and  this  heat  should  be  absorbed  in  a  suf- 
ficient quantity  of  water  to  insure  that  no  part  will  become 
heated  enough  to  become  dangerous. 

(2)  There   should    always    maintain    a    constant    uniform 
pressure,  sufficient  to  insure  a  rapid  flow  of  gas  to  the  torch : 
but  never  more  than  29  pounds.     A  pressure  of  29  pounds  at 
any  point  may  become  a  source  of  danger  and  more  than    15 
pounds  is  unnecessary. 

(3)  It  should  be  well  constructed,  built  of  good  material 
selected  to  resist  the  chemical  action  of  the  gases  and  carbide,  of 
sufficient  weight  and  proportion  to  withstand  the  stress  of  care- 
less handling.     It  should  be  built  for  service,  and  not  merely  to 
sell. 

(4)  It  must  be  simple.     Void  of  numerous  or  complicated 
mechanisms,  easy  to  clean  and  recharge,  and  reliably  automatic 
in  operation. 

(5)  It  should  generate  the  maximum  amount  of  clean  washed 
gas. 

(6)  It  must  be  so  designed,  that  if  any  part  fails  to  work, 
becomes  broken  or  dislodged,  it  will  result  in  stopping  the  carbide 
feed. 

(7)  The  feed  regulator  should  be  actuated  by  the  combined 
influences  of  lowering  pressure  and  flow  of  gas  to  the  service 
pipe;  and   should  not  be   actuated  by   either  one   of  these   in- 
fluences alone. 

(8)  It    should    be    equipped    with    pressure    gauge,    safety 
valve,  and  an  interlocking  arrangement  of  the  valve  handles  that 
will  preclude  the  possibility  of  careless  manipulation.     In  other 
words  it  should  be  "fool  proof." 

Generators  of  the  carbide  to  water  type  are  undoubtedly 
the  best.  With  the  water  in  excess,  it  is  impossible  for  the  tem- 
perature to  rise  to  the  boiling  point  of  water,  and  under  all  con- 
ditions this  class  of  generator  yields  the  purest  gas.  As  the 
acetylene  bubbles  up  through  the  water  it  is  washed  free  from 


A  ( '  i<: T  Y  i ,  K  N  i-:  ( ;  K  N  K  R  A  TC  )  K  s 


49 


most  of  its  impurities.  They  are  perfectly  safe  to  move  on 
trucks  while  charged,  and  under  pressure  and  it  is  impossible 
for  them  to  explode  if  they  are  designed  and  constructed  on  the 
lines  prescribed. 


MODERN  ACETYLENE  GENERATOR 


50 

CHAPTER  VI. 
OXY-ACETYLENE  TORCHES. 


FIG.  15. 
MODERN  OXY-ACETYLENE  WELDING  TORCH 

To  the  casual  observer,  the  oxy-acetylene  torch  is  comparative- 
ly a  simple  construction  consisting  of  a  body  or  handle  at  one 
end  and  a  mixing  head  at  the  other  end,  equipped  with  tips  or 
nozzles  of  various  sizes  to  direct  the  flame  against  the  work ;  but 
the  requirements  of  this  torch  are  very  exacting. 

The  velocity  of  propagation  of  the  oxy-acetylene  flame  is 
about  330  feet  per  second,  and  to  prevent  the  flame  flashing 
back  into  the  torch  head,  it  is  necessary  that  the  velocity  of 
the  gases,  as  they  leave  the  torch,  should  equal  or  exceed  this 
velocity.  This  "flashing  back"  is  a  condition  in  which  the  flame 
enters  the  end  of  the  torch  and  follows  back  into  the  mixing 
chamber.  This  feature  in  a  torch  is  very  annoying  and  causes 
much  delay,  for  it  necessitates  turning  off  the  gases,  relighting 
the  torch,  and  adjusting  the  flame,  before  proceeding.  While 
this  is  being  done  the  work  is  cooling,  thus  the  delay  and  incon- 
venience amounts  to  more  than  merely  relighting  and  adjusting 
the  torch. 

Acetylene  when  burned  in  the  air  requires  about  five  times 
its  volume  of  oxygen  to  completely  consume  it.  This  is  also 
true  when  burning  acetylene  with  the  oxy-acetylene  torch;  but 
to  obtain  the  best  results,  it  is  necessary  to  only  supply  one 
volume  of  oxygen  to  one  volume  of  acetylene,  the  other  four 
volumes  of  oxygen  being  supplied  by  the  air.  If  more  or  less 
than  one  volume  of  oxygen  is  delivered  by  the  torch,  it  results 
in  waste  of  oxygen,  or  lowering  temperature. 


ACETYLENE  TORCHES  51 

The  intense  heat  obtainable  with  this  torch  is  dependent  on 
the  rapidity  of  combustion  and  this,  in  turn,  depends  on  the 
thorough  mingling-  of  the  gases,  so  that  each  atom  of  oxygen  is 
in  close  association  with  a  molecule  of  acetylene,  ready  for 
instant  combination. 

To  obtain  this  thorough  mixture  of  equal  quantities  of  gas 
and  eject  them  at  the  required  velocity,  is  more  difficult  to  ac- 
complish than  might  be  supposed.  The  factors  that  contribute 
to  this  difficulty  are,  the  difference  in  specific  gravity  of  the 
gases,  the  different  pressures  at  which  they  are  supplied,  and  the 
varying  quantities  required  by  the  different  tips. 

Another  feature  to  be  obtained  in  a  good  torch,  is  that  it 
should  handle  well,  or  be  well  balanced  to  facilitate  easy  and 
rapid  manipulation.  When  the  torch  is  being  used  for  welding 
it  is  in  constant  motion,  describing  little  circles  of  uniform  size 
overlapping  each  other  and  equally  spaced  along  the  line  of  the 
weld.  The  motion  is  somewhat  similar  to  that  of  the  penman 
writing  a  series  of  overlapping  loops  in  a  continuous  uninterrupted 
line.  The  reader  has  perhaps  practiced  this  exercise  in  penman- 
ship, and  knows  the  importance  in  having  a  pen  that  handles 
right.  A  well  balanced  torch  is  of  equal  necessity  to  the  welder. 

The  foregoing  requirements  are  general  and  apply  to  torches 
of  either  the  high  or  low  pressure  types. 

According  to  the  pressure  of  the  acetylene  supply,  oxy-acety- 
lene  torches  are  of  two  types,  the  low  pressure  torch,  which  is 
designed  to  use  acetylene  at  a  tension  of  only  a  few  ounces,  and 
the  high  pressure  torch  designed  to  receive  acetylene  at  a  pres- 
sure ranging  from  2  to  12  pounds. 

Low  Pressure  Torches: — To  obtain  the  desired  velocity  at 
the  tip  of  the  torch,  the  oxygen  must  be  delivered  at  high 
pressure,  and  to  provide  equal  volumes  of  gases,  at  such 
a  difference  in  pressure,  it  is  necessary  to  utilize  the  velocity  of 
the  oxygen  to  promote  the  flow  of  acetylene.  This  is  accom- 
lished  by  a  device  similar  to  the  injector,  or  aspirator.  The  oxy- 
gen nozzle  opens  into  the  center  of  a  conical  chamber,  where  it 
draws  in  the  acetylene,  mixes,  and  is  then  ejected  through  an  ex- 


52  OXY-ACETYLENE    WELDING    AND    CUTTING 

pansion  chamber  where  the  velocity  is  reduced  to  a  suitable  value. 

The  oxygen  being  supplied  at  a  pressure  so  greatly  in  excess 
to  that  of  the  acetylene,  it  is  thought  possible  for  it  to  blow 
back  through  the  acetylene  tubes,  and  produce  in  them  a  com- 
bustible mixture,  in  fact  the  first  inventors  of  low  pressure 
torches  greatly  feared  the  "flashing  back"  of  the  flame  into  the 
acetylene  pipes,  and  to  prevent  this  they  devised  many  ingenious 
arrangements,  which  are  still  indispensable. 

High  Pressure  Torches: — The  design  of  high  pressure  torch 
is,  in  a  general  way,  on  the  same  lines  of  the  low  pressure  torch. 
That  is  the  injector  principle  is  used ;  but  not  to  so  great  an  extent. 

The  acetylene  and  oxygen  being  used  at  nearly  the  same  pres- 
sure, there  is  no  tendency  for  the  oxygen  to  blow  back  into  the 
acetylene  tube.  A  more  perfect  mixture  of  gases  is  obtained,  be- 
cause the  oxygen  does  not  tend  to  force  a  passage  way  through 
the  acetylene;  but  remains  in  association  with  it  long  enough  to 
become  thoroughly  mingled.  This  results  in  greater  economy. 

The  high  pressure  torch  is  more  universal  in  application,  be- 
cause flames  of  different  magnitude  are  obtainable  by  regulating 
the  valves  which  control  the  gas  supply,  while  with  the  low 
pressure  it  is  necessary  to  change  the  nozzles  and  mixing  cham- 
bers. In  consequence  of  these  advantages  there  is  a  growing 
favor  for  high  pressure  torches. 

To  facilitate  welding  in  inaccessible  places  and  permit  their 
use  in  welding  machines,  high  pressure  torches  are  constructed 
in  a  variety  of  lengths  and  shapes,  a  few  of  which  are  illustrated. 
Fig.  15  shows  a  torch  designed  for  general  hand  use.  It  is  provid- 
ed with  "tips"  or  nozzles  of  different  sizes,  and  by  inserting  one 
or  the  other,  as  the  occasion  may  require,  the  widest  range  of 
work  may  be  handled,  varying  from  the  thinnest  sheet  iron  to 
the  heaviest  steel  casting.  Table  XI,  in  the  back  of  this  volume, 
gives  the  size  of  tip  best  suited  to  the  weight  of  the  metal  be- 
ing welded,  and  shows  the  amount  of  gases  each  tip  will  con- 
sume per  hour. 

When  large  castings  have  been  preheated  to  considerable 
extent,  the  heat  which  they  radiate  to  the  atmosphere,  makes  it 
very  uncomfortable  for  the  welder  to  stand  over  them  and  use 


ACETYLENE  TORCHES 


FIG.  16. 
OXY-ACETYLENE  TORCH. 

This  torch  is  made  longer  than  the  standard,  to  facilitate  welding  in 
places  the  operator  cannot  approach  on  account  of  inacessibility  or 
radiating  heat. 

the  torch.  In  these  instances  it  is  sometimes  more  convenient 
to  use  a  torch  of  unusual  length,  so  that  the  welder  may  stand 
at  a  more  comfortable  distance.  These  long  torches  are  fre- 
quently used  to  reach  a  weld  that  is  impossible  for  the  welder  to 
approach  on  account  of  it  being  inaccessible.  These  torches 
may  be  made  any  length  to  suit  the  welder  or  the  occasion ;  but 
experience  has  demonstrated  that  when  the  length  exceeds  36" 
the  torch  becomes  difficult  to  handle.  On  this  account,  torches 
for  this  purpose  are  usually  made  about  34"  long. 

All  of  the  standard  torches  are  constructed  to  direct  the  flame 
down  at  a  right  angle  to  the  handle,  or  at  an  angle  varying  lightly 
from  this  position.  This  arrangement  makes  it  impossible  to  do 
welding  in  the  bottom  of  a  tank  which  is  too  small  for  the  welder 
to  enter,  and  to  facilitate  work  of  this  kind,  the  manufacturers 
have  provided,  what  might  be  called  a  Straight  Line  Torch.  In 
this  torch  the  head  and  mixing  chamber  are  arranged  to  deliver 
the  flame  straight  away  from  the  operator,  or  in  a  line  with 
the  handle. 

Cutting  Torches'. — Steel  plates  1-8  or  3-16  inches  thick  may 
be  readily  cut  by  the  oxy-acetylene  process  without  any  special 
changes  in  the  torches  just  described;  but  for  greater  thick- 
nesses a  special  torch  is  required. 


FIG.  17. 
STRAIGHT  LINE  TORCH. 


54  OXY-ACETYLENE    WELDING    AND    CUTTING 

A  complete  description  of  the  oxy-acetylene  cutting  process 
is  described  in  chapter  XII. 

The  principle  upon  which  the  cutting  torch  is  constructed  is 
to  provide  a  flame  to  raise  the  temperature  of  the  metal  to  red- 
ness and  then  deliver  a  jet  of  pure  oxygen  against  the  heated 
surface.  Some  of  the  earlier  torches  resembled  the  regular 
welding  torch  with  the  addition  of  an  auxiliary  oxygen  tube. 
This  tube  received  its  supply  of  oxygen  from  a  point  in  the 
handle  beyond  the  control  of  the  needle  valves  which  regulate 
the  flame ;  and  delivered  its  oxygen  close  beside  the  base  of  the 
flame. 


FIG.  18. 
OXY-ACETYLENE  CUTTING  TORCH. 

It  is  provided  with  a  valve  to  regulate  the  flowr  of  oxygen, 
independent  of  the  supply  required  by  the  preheating  flame. 

There  are  several  features,  of  this  type  of  torch,  that  are  well 
to  consider.  The  greatest  economy  and  speed  are  obtained  with 
the  purest  oxygen.  In  fact  there  is  considerable  effort  expended 
in  generating  and  maintaining  pure  oxygen  for  this  purpose ; 
but  in  torches  of  this  type,  if  the  oxygen  is  polluted  with  air  just 
at  the  moment  it  is  to  be  used,  the  results  are  not  as  satis- 
factory as  they  might  have  been,  if  the  jet  of  oxygen  had  been 
protected  from  the  atmosphere. 

Since  the  preheating  flame  must  precede  the  oxygen  jet  in 
the  line  of  the  cut,  it  follows  that  these  torches  can  only  be  ad- 
vanced in  one  direction,  that  is,  with  the  oxygen  jet  following 


ACETYLENE  TORCHES  55 

• 

the  flame.  Then,  to  cut  a  hole  through  a  plate,  the  operator 
would  have  to  take  different  positions  around  the  plate.  In 
other  words  he  would  either  have  to  walk  around  his  work  or 
assume  some  exceedingly  awkward  positions  to  keep  the  oxygen 
jet  continually  in  the  rear  of  the  preheating  flame. 

Manufacturers  of  modern  torches  have  overcome  these  dif- 
ficulties by  placing  the  oxygen  jet  inside  of  the  heating  flame, 
where  it  is  protected  from  the  surrounding  air,  and  is  ever  in  a 
position  to  do  its  work,  irrespective  of  the  direction  the  torch 
is  being  moved. 

When  the  occasions  for  using  the  cutting  torch  are  frequent 
and  interrupted,  it  is  desirable  to  possess  a  torch  designed  ex- 
clusively for  this  purpose;  but  if  the  events  of  its  use  are  only 
incidental,  an  attachment  may  be  applied  to  the  welding  torch, 
which  will  admirably  serve  the  purpose  of  the  cutting  torch,  and 
give  as  perfect  satisfaction. 

One  or  these  attachments  is  illustrated  in  Fig.  19  which  shows 
the  Vulcan  Combination  Cutting  and  Welding  Torch.  This 
combination  consists  of  an  auxiliary  oxygen  tube  and  cutting 
head,  which,  when  attached  to  the  Vulcan  welding  torch,  makes 
a  perfect  cutting  torch  of  the  modern  type ;  the  preheating  flame 
is  formed  in  a  hollow  annular  cone,  with  the  oxygen  cutting  jet 
in  its  center,  as  described  in  a  previous  paragraph. 


N 


M 


FIG.  19. 
VULCAN  COMBINATION  CUTTING  AND  WELDING  TORCH. 


56  OXY- ACETYLENE    WELDING    AND    CUTTING 

• 

Instructions  on  Assembling.  Vulcan  combination  and  weld- 
ing torches  are  furnished  assembled  and  ready  to  use,  but  when 
a  customer  has  previously  purchased  a  welding  torch,  and  at 
a  later  period  orders  a  cutting  attachment,  he  may  require  some 
instructions  on  how  to  assemble  the  combination. 

Assembling  these  parts  is  only  the  work  of  a  very  few  moments, 
and  if  the  same  routine  is  followed  each  time,  the  performance 
becomes  habitual,  and  the  combination  is  made  very  quickly, 
without  distracting  the  operator's  attention  from  other  work. 
An  outline  of  procedure  is  recommended  as  follows,  the  parts 
and  letters  referred  to  are  indicated  in  Fig.  19. 

To  quickly  assemble  this  combination,  unscrew  the  union 
nut  C  and  remove  the  cutting  head  from  the  tube. 

Then  attach  cutting  head  to  the  head  of  the  torch  by  screw- 
ing A  into  B  up  to  the  shoulder  on  A,  and  tighten  by  hand.  If 
the  cutting  head  does  not  align  with  the  torch  it  should  be 
made  to  do  so,  by  loosening  the  nut  D  and  swinging  it  to  the 
position  shown  in  the  illustration.  When  this  position  has  been 
obtained  the  nut  D  must  be  screwed  down  tight  onto  the  cutting 
head. 

The  small  machine  screw  H  should  then  be  removed  from 
the  clamp  G  and  the  clamp  slipped  over  the  handle  on  the  torch 
at  I. 

Attach  E  to  F  and  attach  the  tube  to  the  cutting  head  by  re- 
turning the  union  nut  C  to  its  original  position  shown  in  the  il- 
lustration. Then  replace  and  tighten  the  machine  screw  H. 

See  that  the  thumb  lever  O  is  up  in  the  released  position, 
which  closes  the  oxygen  valve  J,  and  close  the  needle  valves  L 
and  M. 

The  torch  is  now  ready  to  be  connected  with  the  hose.  At- 
tach the  red  acetylene  hose  to  the  lower  connection  and  the 
black  oxygen  hose  to  the  recently  applied  upper  connection. 

The  oxygen  and  acetylene  gases  are  ignited  at  R  and  the 
tips  N  are  not  used  in  cutting. 


ACETYLENE  TORCHES 


57 


To  remove  the  cutting  attachment,  disconnect  the  oxygen 
hose,  remove  machine  screw  H,  disconnect  E  and  C  and  remove 
the  oxygen  tube  by  slipping  clamp  G  from  the  handle  of  the 
torch ;  then  unscrew  A  from  B,  attach  the  black  oxygen  hose  to 
the  upper  connection  K,  select  a  tip  from  N  and  insert  it  into  B. 
The  torch  is  then  ready  to  use  for  welding. 

Figure    18   shows   the   complete  combination   torch. 


FIG.  20. 
TORCH  DESIGNED  FOR  WELDING  MACHINES. 


58 

CHAPTER  7. 

PRESSURE  REGULATORS. 

When  oxygen  or  acetylene  is  obtained  in  drums  at  pressures 
ranging  between  150  and  1,800  per  square  inch  and  used  at  the 
torch  at  pressures  ranging  from  i  to  54  pounds,  it  becomes  neces- 
sary to  employ  some  automatic  mechanism  that  will  make  this 
reduction,  and  maintain  a  constant  uniform  pressure  at  the 
torch,  irrespective  of  the  original  and  constantly  diminishing 
pressure  in  the  drums. 

The  device  used  to  perform  this  work,  is  known  among  weld- 
ers as  an  automatic  regulator  and  accomplishes  this  regulated 
pressure  reduction  by  automatically  throttling  the  gas  supply  so 
that  the  pressure  will  remain  uniform  at  the  torch.  As  the  gas 
enters  the  regulator  it  passes  through  a  valve  into  an  expansion 
chamber,  one  side  of  which  is  a  flexible  diaphragm.  If  the  quant- 
ity of  gas  entering  this  expansion  chamber  exceeds  the  quantity 
going  out  to  the  torch,  there  will  be  a  natural  tendency  to  in- 
crease the  pressure,  but  this  increasing  pressure,  deflects  the  dia- 
phragm and  partially  closes  the  valve ;  thus  the  gas  is  admitted  or 
throttled  to  suit  the  increasing  or  diminishing  demand  at  the 
torch. 


Fig.  21 
Al'TOMATIC  ACETYLENE  REGULATOR 


PRESSURE    REGULATORS  -,t> 

These  regulators  are  provided  with  a  spring  and  adjusting 
screw  arranged  to  bear  directly  on  the  diaphragm,  so  that  the 
final  pressure  may  be  adjusted  to  suit  the  requirements  of  the 
work. 


Fig.  22 
AUTOMATIC  OXYGEN  REGULATOR 

They  are  usually  provided  with  one  or  two  gauges  to  indicate 
the  pressures  in  the  drum  and  at  the  torch. 

A  low  pressure  regulator  equipped  with  one  indicator  is  shown 
in  Figure  21.  The  indicator  dial  shows  the  pressure  of  gas  going 
to  the  torch,  and  the  T  handle  on  the  front  is  used  to  adjust  this 
pressure  as  the  requirements  demand. 

This  type  regulator  is  usually  used  on  acetylene  generators,, 
because  in  this  service  it  is  only  required  to  know  the  pressure  of 
the  gas  going  to  the  torch,  the  pressure  in  the  generator  being 
indicated  by  an  independent  gauge. 


60 


OXY- ACETYLENE    WELDING    AND    CUTTING 


A  high  pressure  regulator  with  two  indicators  is  shown  in 
Figure  22.  One  indicator  shows  the  pressure  in  the  drum,  and 
the  other  the  pressure  of  the  gas  going  to  the  torch.  When  used 
on  oxygen  drums  the  high  pressure  indicator  is  useful  in  deter- 
mining the  amount  of  gas  in  the  drum  as  explained  on  page  26, 
it  is  therefore,  sometimes  called  an  Oxygen  Regulator, 


Fig.  i>:; 
OXY-ACETYLENE    WELDING    PLANT 

Showing    application    of    automatic    pressure    regulators 


ACKTVLKXK  GENERATOR 

CHAPTER  8. 


61 


Fig.  ;iO 
VULCAN   AUTOMATIC   ACETYLENE   GENERATOR 

Chapter  five  outlines  the  various  types  of  generators  that  can 
be  used  to  produce  acetylene  gas.  In  reading  over  the  advantages 
and  disadvantages  of  the  different  methods  of  generating  ace- 
tylene, it  will  be  noted  that  the  "carbide  to  water  feed"  genera- 
tor has  none  of  the  disadvantages  of  the  other  types,  but  does 
have  a  great  many  advantages  that  are  not  possessed  by  the  others. 

Of  the  two  styles  of  generators,  low  and  medium  pressure, 
the  latter  is  the  better  for  welding,  because  the  acetylene  and 
oxygen,  should  be  delivered  to  the  mixing  chamber  of  the  weld- 
ing torch  at  as  near  the  same  pressure  as  can  be  secured. 


62  OX Y- ACETYLENE    WELDING    AND    CUTTING 

\Yhere  both  gases  are  thus  combined  under  positive,  even 
pressure  their  mixture  is  more  complete — assuming  that  the  mix- 
ing chamber  of  the  torch  is  properly  constructed.  Unless  this 
thorough  mixing  of  the  two  gases  takes  place,  the  -result  will  be 
incomplete  combustion,  hence  waste  of  gas  and  loss  in  efficiency. 

With  the  low  pressure  or  gasometer  type  of  generators,  the 
injector  type  of  torch  is  principally  used.  By  this  is  meant  that 
oxygen  under  high  pressure,  in  passing  through  the  mixing  cham- 
ber of  the  torch,  sucks  the  acetylene  through  with  it.  In  this 
way  the  two  gases  are  not  thoroughly  mixed,  and  the  result  is  a 
waste  of  gas  and  a  poor  weld.  The  feeding  mechanism  of 
most  pressure  generators,  now  on  the  market,  are  operated  by 
means  of  complicated  clock-work  with  pulleys  and  weights,  leath- 
er diaphragms,  etc.  These  frequently  get  out  of  order  at  just 
the  time  when  operator  needs  the  gas  the  most  and  the  resulting 
delays  are  expensive  as  well  as  annoying. 

The  Vulcan  automatic  acetylene  generator  works  on  entirely 
new  principles,  and  the  features  that  contribute  to  its  success  are 
so  simple,  unique,  and  perform  their  duty  so  accurately  that  the 
generator  is  well  worth  consideration. 

Its  design  is  such  that  the  demand  for  gas  or  the  flow  of  gas 
to  the  service  pipe,  working  in  conjunction  with  the  amount  of 
pressure  in  the  generator,  automatically  regulates  the  gas  genera- 
tion to  meet  the  varying  demand  at  a  uniform  pressure.  The 
rate  at  which  the  carbide  is  fed  into  the  water  varies  directly 
with  the  rate  at  which  the  gas  is  used,  and  no  more  carbide  is 
fed  than  is  absolutely  necessary  to  maintain  the  pressure  at  that 
particular  moment.  If  gas  is  being  used  and  pressure  up  to 
normal,  or  vice-versa  if  the  gas  is  not  being  used  but  the  pres- 
sure below  normal,  the  carbide  feed  is  inactive;  but  under  these 
conditions  a  very  slight  drop  in  pressure,  or  the  renewed  de- 
mand for  gas  will  cause  the  right  amount  of  generation  to  take 
care  of  the  moment's  demand. 

The  carbide  feed  automatically  drops  small  quantities  of  1^4 
x^£  carbide,  deep  into  a  liberal  quantity  of  water,  and  as  the  gas 
bubbles  rise  to  the  surface,  they  are  cooled  and  washed,  and 
emerge  free  from  dust  or  other  impurities 

By  the  arrangements  set  forth,  many  advantages  are  obtained. 


AC  ET  YL  UN  E  G  K  X  K  R  A  TO  R 


63 


The  most  apparent  of  which  is  a  very  constant  uniform  pres- 
sure. After  generation  is  eliminated  on  account  of  there  being 
only  a  very  small  quantity  of  carbide  dropped  at  one  time,  and 
the  gases  are  cool  because  there  is  not  sufficient  reaction  taking 
place  to  perceptibly  raise  the  temperature  of  the  large  volume 
of  water.  The  ij^x^  carbide  used  in  this  machine  generates 
one  half  a  cubic  foot  more  gas  per  pound,  than  the  quarter  or 
finely  crushed  carbide,  and  since  all  sizes  of  carbide  are  re- 
tailed at  the  same  price  this  feature  alone  effects  a  saving  of 
12^2  per  cent  in  the  cost  of  generation.  The  motor  that  operates 
the  carbide  feed  is  imposed  between  the  generating  chamber 
and  the  service  pipe,  and  for  the  reason  that  it  is  not  operated 
by  the  deminishing  gas  pressure  only,  but  by  the  flow  of  gas  to 
the  service  pipe  combined  with  reducing  pressure,  the  arrange- 
ment is  an  assurance  that  all  the  carbide  will  not  be  fed,  or  an 
excessive  amount  of  gas  generated,  should  the  gas  holder  be 
accidentally  punctured.  The  last  mentioned,  is  a  common  fault 
of  generators  actuated  by  reduced  gas  pressure  only. 


Fig.  31 
VULCAN   GENERATOR   WELDING   PLANT 


64  OXY-ACETYLENE    WELDING    AND    CUTTING 

A  word  about  the  unique  features  of  the  motor  will  interest  the 
reader.  The  runner  or  wheel  from  which  power  is  received  is 
entirely  incased  and  not  visible,  but  when  removed  it  resembles 
an  old-fashioned  over-shot  water-wheel.  With  the  water-wheel 
power  is  derived  from  the  weight  of  the  water,  in  the  buckets, 
descending  and  rotating  the  wheel ;  but  the  wheel  of  the  Vulcan 
motor  is  submerged  in  water  and  operated  by  the  buoyancy  of  the 
gas  gathering  under  the  inverted  concave  buckets  and  rotating  the 
wheel,  in  its  ascent  from  the  generating  chamber  to  the  service 
pipe.  The  arrangement  is  such  that  if  the  pressure  is  up  to  nor- 
mal, the  gas  is  diverted  through  a  by-pass,  to  the  service  pipe, 
without  rotating  the  motor. 

In  this  description  the  reader  will  note  the  absence  of  springs, 
clock-work  or  weights  which  might  make  the  apparatus  cum- 
bersome. 

The  generator  is  designed  to  deliver  gas,  at  twelve  pounds 
pressure,  to  oxy-acetylene  welding  and  cutting  torches.  The  pres- 
sure selected  is  deemed  most  suitable  for  the  work. 

The  suggestions  and  rules  of  the  consulting  engineers  of  the 
National  Board  of  Fire  Underwriters  are  strictly  followed,  in  the 
manufacture  and  construction  of  Vulcan  Acetylene  Generators, 
and  every  precaution  has  been  taken  to  insure  safety  and  effi- 
ciency. The  materials  are  the  best,  the  proportions  ample,  and  the 
workmanship  accurate,  so  that  with  proper  handling  the  opera- 
tion will  be  eminently  successful.  To  insure  that  these  generators 
will  be  properly  handled  by  even  the  most  careless  operators, 
each  generator  is  equipped  with  a  system  of  guards  so  inter- 
locked that  it  is  impossible  for  an  absent-minded  operator  to  make 
mistakes.  In  fact  there  is  only  one  way  they  can  be  manipulated, 
and  that  is  the  right  way.  Although  it  is  impossible  to  pursue 
wrong  methods  in  operating  this  plant  we  will  outline  the  prop- 
er method.  In  this  outline  the  parts  referred  to  are  indicated  in 
Figure  32. 

Pipe  No.  i  is  the  blow-off  and  should  be  extended,  without 
traps  and  as  few  elbows  as  possible,  to  the  outside  of  the  building, 
and  the  end  pointed  down  to  exclude  snow,  birds,  etc.  Pipe  Xo. 
2  is  the  service  pipe  and,  if  the  shop  is  piped,  it  should  be  con- 
nected to  the  supply  line,  but  if  it  is  intended  to  use  gas  directly 


ACKTYLKXK  GKXKRATOR 


65 


from  the  generator,  though  the  hose,  connect  pipe  No.  2  with 
the  acetylene  regulator. 

Fill  the  chamber  No.  3  and  motor  case  No.  4  with  water 
through  hole  No.  5  and  allow  to  stand  a  few  minutes  for  air  bub- 
bles to  work  out. 


Fig.  32 
INTERIOR   OF  VULCAN   GENERATOR 

Before  replacing  the  plug  into  No.  5  be  sure  the  motor  case  is 
filled  to  overflowing. 

To  charge,  or  recharge  the  generator  relieve  the  pressure  by 
turning  lever  No.  6  one-quarter  turn  to  the  right,  then  agitate 
the  sediment  so  it  will  run  out,  by  rotating  the  crank  No.  7.  Open 
the  locking  device  by  turning  handle  No.  8  one-quarter  turn  to 


H6  OX Y- ACETYLENE  WELDING  AND  CUTTING 

the  left.  Draw  off  the  sediment  through  sludge  cock  by  turning 
handle  No.  9  one-quarter  turn  to  the  left.  After  draining,  close 
sludge  cock  before  proceeding  further. 

Now  swing  lever  No.  10  to  a  horizontal  position  and  fill  the 
lower  part  of  the  generator  with  water  through  funnel  No.  n 
until  it  overflows  through  No.  12;  then  return  handle  to  No.  10 
to  its  original  vertical  position.  Remove  cover  No.  13,  fill  the 
carbide  hopper  with  ij4x^carbide,  replace  cover  and  tighten 
cap  screws  even  and  equally.  Lock  up  the  generator  by  swinging 
lever  No.  8  to  the  right  in  its  original  position  and  closing  lever 
No.  6  to  the  left  over  it.  Put  valve  handle  No.  14  in  a  vertical 
position  which  closes  the  service  cock. 

The  generator  is  now  ready  for  pressure  which  is  started  by 
rotating  gear  wheel  No.  15  to  the  left  until  the  pressure  gauge 
indicates  about  three  pounds.  The  carbide  wrill  then  feed  auto- 
matically and  the  pressure  rise  to  the  proper  amount  as  soon 
as  the  service  cock  is  opened  and  a  little  gas  drawn  off  through 
the  torch. 

From  this  on  the  Vulcan  Generator  is  entirely  automatic  and 
needs  no  further  attention  until  the  contents  are  entirely  ex- 
hausted. 

On  account  of  these  generators  being  self  contained,  com- 
pact in  form,  and  complete  without  the  necessity  of  a  cumber- 
some gasometer,  they  are  very  suitable  for  portable  purposes. 

One  of  these  generators  mounted  on  a  truck,  with  oxygen 
drums  and  tool  box,  is  shown  in  Figure  33.  This  makes  a  com- 
plete portable  plant  which  may  be  taken  to  the  work  anywhere 
about  the  shop  or  yards. 

Vulcan  Generators  are  Safe  because  there  is  less  surface  sub- 
jected to  injury  than  in  many  other  types. 

There  are  no  pipe  connections  between  widely  separated  parts. 
They  are  less  liable  to  freeze  than  generators  having  gasometers. 
Every  movable  part  is  safe  guarded  in  a  way  that  makes  them 

fool  proof. 
The  carbide  charge  cannot  be  accidentally  discharged  into  the 

•    water. 
It  cannot  be  overfilled  with  water. 


ACETYLENE  GENERATOR 


67 


Fig.  :;:; 
VULCAN  PORTABLE  GENERATOR  PLANT 


68  OXY-ACETYLENE  WELDING  AND  CUTTING 

CHAPTER  9. 

OPERATING  PLANTS. 

This  might  be  more  correctly  called  operating  a  welding  shop, 
for  it  is  the  writer's  intention  to  call  attention  to  a  few  of  the 
essential  details,  both  in  equipping  and  operating  a  shop.  The 
subject  covers  such  a  range  of  information,  that  it  would  be  im- 
possible to  mention  every  detail,  in  fact  it  would  not  be  practical 
to  undertake  such  a  task,  for  the  equipment  will  be  great  or 
small,  according  to  the  amount  and  nature  of  the  work  which  the 
operator  expects  to  provide  for. 

Whether  the  amount  of  work  is  considerable  or  not,  there  is 
one  thing  that  should  be  uppermost  in  the  mind  of  the  operator, 
that  is  thoroughness  and  excellency  of  work.  No  matter  how 
small  or  how  large  the  job,  the  welding  should  be  thoroughly, 
carefully  and  conscientiously  performed.  After  a  job  has  been 
finished  it  is  often  difficult  to  determine  whether  it  is  well  done 
or  not,  this  information  may  only  be  obtained  by  observing  the 
welder  while  he  is  doing  his  work  or  testing  the  weld  after  it  has 
been  finished.  Sometimes  it  is  impractical  to  do  either  of  these, 
and  the  integrity  of  the  welder  must  be  relied  upon. 

Recognizing  this  truth,  it  is  often  the  practice  of  boiler  in- 
spectors, to  condemn  any  welding  on  boilers  which  has  not  been 
done  by  welders  of  "known  reputation,"  and  since  boiler  work 
covers  a  large  per  cent  of  the  field  of  his  usefulness,  the  welder 
should  make  every  effort  to  get  into  the  class  of  welders  of 
"known  reputation."  This  also  applies  to  other  kinds  of  work. 
The  occasions  that  require  autogenous  welding  are  frequently 
of  great  importance.  It  may  be  a  crank  shaft  or  cylinder  for 
some  power  plant,  and  if  the  welder  does  his  work  thoroughly, 
the  job  will  hold  and  be  as  good  as  a  new  piece ;  but  if  he  is  hasty 
or  careless  it  will  be  very  liable  to  fail,  resulting  in  loss  of  time, 
money  and  possibly  loss  of  life.  For  this  reason  persons  who 
have  work  of  this  kind  are  wont  to  patronize  welders  of  "known 
reputation." 

In  work  of  the  kind  just  described,  the  saving  in  time  and 
money  is  sufficient  to  pay  the  welder  handsomely  for  all  the 


OPERATING   PLANTS  09 

time,  care,  or  expense  he  may  devote  to  thoroughly  doing  his 
work  and  there  is  no  excuse  for  slighting  the  job  on  the  pretext 
that  his  customer  will  object  to  the  expense.  The  only  com- 
plaint that  could  justly  be  made,  would  be  for  time  covered  by 
idleness,  for  lack  of  foresight  that  may  cause  loss  of  time  or  de- 
lay, or  charging  for  a  service  which  you  are  not  equipped  to 
render. 

Any  equipment  the  welder  can  provide,  will  lessen  the  cost 
of  the  work  and  often  facilitate  better  work.  Therefore  equip- 
ment sufficient  for  the  work  you  expect  to  handle  is  an  asset, 
which  can  hardly  be  dispensed  with.  Such  conveniences  as  an 
assortment  of  handy  tools  arranged  within  easy  reach,  benches, 
brick  welding  tables,  preheating  furnaces,  and  facilities  for  hand- 
ling heavy  work,  contribute  to  good  service  and  the  pleasure 
of  work,  and  are  conveniences  that  may  be  built  and  installed 
during  ones  spare  moments. 

Many  welders  have  started  their  plant  in  a  very  modest  way, 
buying  their  gases  in  drums  and  in  every  way  curtailing  the 
amount  of  the  original  investment.  As  their  business  grew  their 
mind  was  occupied  in  pursuing  their  trade,  and  the  fact  that 
their  acetylene  was  costing  them  more  than  twice  as  much  as  it 
should,  did  not  occur  to  them  until  they  learned  that  a  competi- 
tor charged  one  cent  a  foot  for  acetylene  and  made  profit  on 
it;  whereas  he  could  not  make  a  profit  on  acetylene  at  2  i-4c  a 
foot.  This  leads  to  the  explanation  that  acetylene  in  drums  has 
an  economic  place  in  plants  that  have  to  be  quickly  transported 
to  some  remote  location,  over  rough  roads,  in  cold  weather  and 
also  in  shops  where  the  occasions  for  using  the  apparatus  are  not 
very  frequent.  The  cost  of  acteylene  in  drums  is  2c  per  foot 
at  the  recharging  station  and  to  this  cost  is  added  freight  and 
cartage,  while  the  cost  of  acetylene  generated  on  the  premises 
of  the  welding  shop,  seldom  exceeds  7-80  per  foot.  In  a  shop 
where  the  welder  uses  the  torch  6  hours  a  day,  the  saving  ef- 
fected, by  generating  his  own  acetylene,  will  amount  to  $2.50 
or  $3.00  per  day. 

In  shops  that  are  provided  with  an  acetylene  generator  it 
is  advisable  to  give  it  a  permanent  location  in  some  corner 
where  it  will  be  out  of  the  way  and  protected  against  freezing. 


70 


OXY- ACETYLENE  WELDING  AND  CUTTING 


The  advantages  of  a  permanent  location  for  the  generator  are 
many.  The  time  used  in  trucking  it  around  the  shops  is  elim- 
inated, the  blow  off  and  sludge  pipes  can  be  extended  to  out- 
side the  building,  water  may  be  piped  to  a  place  convenient  to  the 
generator,  the  generator  will  be  less  liable  to  become  injured 
by  collision,  and  the  acetylene  may  be  piped  to  any  part  of  the 
building  with  drops  and  hose  connections  at  different  places  most 
convenient  to  the  work. 

Piping: — Acetylene  generators  are  usually  regulated  to  con- 
trol the  gas  pressure  at  about  12^  pounds  per  square  inch  and 
since  the  largest  tips  consume  gas  at  very  nearly  this  pressure, 
it  is  essential  that  the  gas  should  be  conveyed  through  the 
pipes  with  as  little  loss  of  pressure  as  possible.  It  is  recom- 
mended that  the  loss  of  pressure  should  not  exceed  8  ounces. 
The  factors  to  be  considered  in  determining  the  loss  in  pres- 
sure are,  the  length  and  diameter  of  the  pipe,  the  specific  grav- 
ity and  the  initial  and  final  pressures  of  the  gas.  The  quantity 
of  acetylene  which  will  be  delivered  through  pipes  of  different 
sizes  with  a  loss  in  pressure  of  8  ounces  from  an  initial  pres- 
sure of  u!/2  pounds,  may  be  calculated  from  the  following 
formula,  in  which  (D)  represents  the  inside  diameter  of  the 
pipe  in  inches  and  (L)  its  length  in  feet. 


2809\ 


26     D 


quanty  of  gas. 


TABLE  IX. 

ACETYLENE  DELIVERED  BY  PIPES  OF  VARIOUS 
SIZES  AND  LENGTHS,  WITH  LOSS  OF  8oz.  PRESSURE 
FROM  AN  INITIAL  PRESSURE  OF  113^  LBS. 


Nominal 
Size  of 

Lengtl 

i  of  Pi] 

)e  in  fe 

et 

Pipe 

100  | 

200 

300 

400 

500*  | 

600 

700 

%  

434 

306 

250 

216 

193 

177 

163 

%  
1  

1%  

872 
1,618 
3,204 

616 
1,144 
2,266 

503 
934 

1,850 

436 

809 
1,602 

390 
723 
1,433 

356 
660 

1,308 

329 
611 

1,211 

OPERATING   PLANTS  71 

In  using  this  table  the  pipe  fitter  should  add  to  the  actual 
length  of  the  pipe,  a  sufficient  length  to  compensate  for  the 
fittings,  as  obtained  from  table  VIII. 

The  effect  of  a  bend  or  sharp  angle  in  a  pipe  is  to  retard  the 
flow  of  gas.  This  is  least  when  the  radius  of  the  bend  is  five 
times  the  radius  of  the  pipe.  The  most  convenient  way  of  stat- 
ing the  resistance  offered  by  bends,  is  in  terms  of  equivalent 
length  of  straight  pipe  which  offers  the  same  resistance  to  the 
flow  as  the  extra  resistance  due  to  the  bend.  A  formula  given 
for  this  equivalent  length  is 


=  12.851-- J 

VR/ 


.83 


L^equivalent  in  feet 

r=radius  of  pipe 

R=radius  of  curve 

l=length  of  curve  in  feet  measured  on  center  line. 

The  following  table  gives  the  additional  length  required  to 
equal  the  friction  due  to  globe  valves.  For  standard  elbows 
and  trees,  take  ^  the  value  given  in  the  table. 

TABLE  VIII. 

ADDITIONAL  LENGTHS  OF  PIPE  THAT  WILL 
CAUSE  FRICTION  EQUAL  TO  THE  FRICTION  DUE  TO 
GLOBE  VALVES. 

Diameter  of  pipe  Additional  length 

in  inches.  in  feet. 

1  2. 

*yt  4 

2  7 

2y2  10 

3  '3 

3^  l6 

4  20 

5  * 

6  36 


72  OXY-ACETYLENE  WELDING  AND  CUTTING 

The  blow-off  or  exhaust  pipe  should  extend  to  the  outside 
of  the  building  with  as  few  elbows  as  possible  and  terminate  with 
the  end  pointing-  down  to  exclude  the  snow  and  water. 

The  sludge  pipe  or  drain  pipe  as  it  is  commonly  called  should 
not  lead  direct  to  a  sewer,  but  should  first  discharge  into  an  open 
pit.  This  pit  may  be  provided  with  an  overflow,  about  3  feet 
above  the  bottom,  which  may  then  lead  to  a  sewer.  The  pipes 
from  the  generator  to  the  pit  should  have  a  fall  of  about  one 
inch  to  twelve  feet  and  from  the  pit  to  the  sewer  one  inch  to 
20  feet.  If  a  sludge  pit  is  constructed  that  will  drain  and  leave 
the  residuum  comparatively  dry,  this  material  may  become  of 
some  pecuniary  value.  The  chief  uses  of  the  sludge,  frequently 
called  acetylene  lime,  are  for  mixing  mortar,  for  whitewashing 
fences,  cattle  pens,  fruit  trees,  etc.,  for  making  paths,  and  for 
fertilizing,  with  some  occasional  application  as  an  insecticide  and 
disinfectant,  mortar  made  from  it  is  reported  to  bind  quickly  and 
hard ;  there  is  no  reason  why  mortar  made  from  it  should  not 
be  at  least  of  equal  value  with  mortar  made  from  slaked  lime. 
It  may  be  added  that  any  of  the  uses  to  which  ordinary  lime 
white  wash  is  applied,  a  white  wash  made  of  carbide  residuum 
answers  equally  as  well. 

In  view  of  the  many  particular  uses  to  which  acetylene  lime 
has  been  successfully  applied,  and  particularly  because  of  its 
usefulness  as  a  fertilizer,  it  may  not  be  out  of  place  to  submit 
the  chemical  analysis  of  carbide  residuum.  The  following  figures 
show  the  analysis  of  three  specimens  of  residue  taken  at  remote 
places. 

i  2  3 

Per  cent     Per  cent     Per  cent 

Sand   (silica)  1.24  i.io  .97 

Carbon    (coke  or  coal)  2.08  3.95  2.14 

Oxide  of  iron  and  aluminum  3.11  2.9  2.3 

Lime  62.5  63.65  66.1 

Water  and   carbonic   acid  31-04  28.4  28.47 

The  services  pipes,  or  mains  that  connect  the  generator  with 
the'  torches  must  be  securely  fastened,  without  sags  that  may 
form  pockets  and  when  practical,  they  should  drain  toward  the 


OPERATING   PLANTS  7.; 

generator.  It  is  advisable  to  use  galvanized  pipe  because  the 
acetylene  is  usually  a  little  moist  and  forms  oxide  of  iron,  which 
comes  off  in  a  powder  and  may  accumulate  in  certain  parts. 
Pipes  of  red  copper  are  strictly  prohibited  because  the  acetylene 
and  copper  can  form  acetylide  of  copper,  which  is  spontaneously 
combustible. 

Testing:  As  soon  as  the  pipes  are  all  in  place  and  are  prop- 
erly secured,  the  system  should  be  tested,  to  find  whether  it  is 
perfectly  gas  tight.  A  convenient  nipple  should  be  selected  for 
making  connection  to  the  proving  pump  (an  ordinary  auto  pump 
will  do),  and  every  other  opening  or  fitting  should  be  tightly 
closed.  The  pump  may  then  be  connected  and  air  forced  into 
the  system  until  the  pressure  gauge  registers  14  or  15  pounds. 
The  pump  should  then  be  shut  off,  leaving  the  gauge  under  press- 
ure. The  extent  of  the  leak  may  be  judged  by  the  rapidity  of  the 
fall  in  pressure;  but  its  location  must  be  found  by  following  the 
pipe  line  and  listening  for  the  hiss  of  escaping  air  and  by  apply- 
ing soapy  water  to  the  joints,  with  a  heavy  brush. 

The  oxycetylene  welding  and  cutting  outfit  is  the  best  tool 
for  making  the  pipe  connections,  for  with  it  the  pipes  may  be 
cut  to  any  length,  heated  for  bending,  and  the  joints  welded.  The 
welded  joints  will  never  leak  or  give  trouble  whereas  screwed 
joints  might  leak. 

After  the  pipes  have  been  thus  inspected  and  proven  satisfac- 
tory, the  pressure  may  be  released,  the  generator  started,  and 
the  gas  pressure  raised  to  12  or  13  pounds.  After  a  little  gas  has 
been  drawn  off  at  the  extreme  ends  of  the  pipe  and  its  branches, 
it  should  be  tightly  closed  and  allowed  to  stand  at  the  pressure 
stated,  for  several  hours.  Then  if  there  are  any  leaks,  their 
presence  will  be  noted  by  the  smell.  A  mixture  of  acetylene  and 
air  in  the  proportion  of  i  to  10000  can  be  clearly  detected  by  the 
smell.  Do  not  hunt  for  leaks  with  a  light. 

Leaks  in  The  Oxygen  Pipes: — Oxygen  is  an  odorless  gas 
and  its  abundance  in  the  room  is  neither  noticeable  nor  harmful, 
but  it  is  certainly  not  a  very  economical  practice  to  allow  it  to 
escape,  although  it  is  not  harmful  nor  explosive  it  may  be  a  source 
of  danger,  if  allowed  to  blow  against  the  clothing  while  the 
torch  is  being  used. 


74  OX Y- ACETYLENE  WELDING  AND  CUTTING 

If  oxygen  is  blowing  against  the  clothes  they  are  extremely 
inflammable  and  will  ignite  with  a  small  spark  from  the  torch,  the 
flames  may  extinguish  themselves  by  evading  the  oxygen,  but  a 
bad  burn  may  result  before  this  is  done. 

Read  Instructions : — Carefully  read  all  the  instructions  attend- 
ing the  apparatus,  go  over  each  piece  and  understand  it  before 
attempting  to  use  it.  This  may  save  long  delays  and  much 
correspondence,  for  it  is  not  an  uncommon  thing  for  manufac- 
tures of  welding  apparatus,  to  receive  complaints  that  the  torch 
would  not  work,  the  tips  would  not  fit,  or  that  parts  were  miss- 
ing and  after  long  correspondence,  learn  that  the  apparatus  was 
all  right;  but  the  customer  had  neglected  to  read  the  instruc- 
tions and  did  not  know  how  to  assemble  his  equipment. 

Welding  Table : — Aside  from  the  work  benches  and  tools,  one 
of  the  first  requisites  of  the  welding  shop  is  the  welding  table. 
Whenever  the  work  to  be  welded  is  not  too  large  or  too  difficult 
to  manipulate,  the  operation  is  best  carried  out  on  a  table. 
These  tables  should  be  entirely  of  metal  except  the  top  which 
may  be  made  of  a  good  grade  of  brick,  preferably  fire  brick. 
The  nature  of  the  work  to  be  handled  on  them,  will,  of  course 
regulate  their  size;  but  a  table  4  feet  by  6  feet  and  24  inches 
high  will  be  best  suited  to  the  average  run  of  work.  For  light 
welding  on  aluminum  work  they  may  be  made  a  little  higher, 
33  inches  being  a  good  height.  These  tables  are  best  built  of 
2*^x2^x3-16  angles  assembled  and  welded  with  the  torch.  The 
welded  joints  give  the  table  rigidity  and  make  the  beginner 
familiar  with  the  work.  The  material  required  for  the  table 
described  above  would  consist  of  4  pieces  of  angle  6  feet  long,  4 
pieces  4  feet  long,  4  pieces  2  feet  long,  and  7  pieces  of  lightei 
material  43  inches  long.  The  6  and  4  feet  lengths  are  welded 
together  at  the  corners  with  one  leg  of  the  angle  standing  verti- 
cal and  the  other  projecting  inward,  making  two  frames  6  feet 
by  4  feet  out  side.  One  of  these  frames  is  used  for  the  table 
top  and  the  other  for  a  tool  tray  beneath.  The  2  foot  lengths 
are  used  for  legs,  fitting  the  inside  of  the  angle  over  the  corners 
of  the  frames  and  welding  them.  The  bottom  of  the  tool  tray 
should  be  about  10  in.  above  the  floor  and  fitted  with  about  16 
gauge  steel  sheet.  The  43  inch  lengths  will  be  spaced  9  inches 


OPERATING   PLANTS  7,-> 

apart  and  welded  between  the  edges  of  the  angles  forming  the 
table  top.  The  top  of  the  horizontal  leg  of  these  angles  will  be 
flush  with  the  horizontal  leg  of  the  angles  forming  the  table  top, 
and  the  vertical  leg  will  extend  below.  Their  purpose  is  to  sup- 
port the  brick  filling,  composing  the  top,  and  for  that  reason 
they  should  be  placed  beneath  the  joints  of  the  brick.  Figure  23 
shows  one  of  these  tables  with  part  of  the  brick  removed  to  ex- 
pose their  support. 


Fig.  23 
WELDING  TABLE  CONSTRUCTED  OF  ANGLE  IRON 

On  these  tables,  there  can  be  built,  temporary  preheating 
furnaces  for  heating  work  preparatory  to  welding,  or  they 
may  be  designed  to  include  permanent  furnaces  formed  in  the 
brick  work  of  their  top.  Here  is  an  opportunity  for  the  welder 
to  display  his  ingenuity  in  designing  a  combined  table  and  pre- 
heating furnace. 

Some  manufactures  build  a  combination  table,  or  more  cor- 
rectly, a  combination  tool  consisting  of  an  iron  table  top  with 
slotted  holes  for  clamping  down  work,  a  long  Y  bar,  blocks 
for  aligning  and  welding  crank  shafts,  and  a  swivel  vise  for 
holding  irregular  shaped  pieces.  The  top  portion  of  the  stand 
incorporates  a  ball  and  socket  joint,  which  permits  rotating  the 
work  or  clamping  it  at  any  angle  that  will  facilitate  easy  manipu- 
lation. The  tool  is  a  great  convenience  and  may  be  classified 


76 


OX Y- ACETYLENE  WELDING  AND  CUTTING 


among  the  time  saving  devices  that  go  to  make  up    an    up-to- 
date  shop. 


Fig.  24 
COMBINATION  WELDING  TABLE 

Preheating  Furnaces: — For  reasons,  which  will  be  described 
fully  under  the  chapter  on  welding,  any  welding  shop  is  in- 
complete without  some  provision  for  preheating  and  slowly 
cooling  his  work.  In  the  absence  of  a  special  furnace  one  should 
always  have  the  material  at  hand  for  building  a  temporary  af- 
fair of  brick  and  sheet  asbestos.  These  are  very  quickly  and 
easily  constructed  and  serve  their  purpose  very  well.  Even  when 
shops  are  equipped  with  permanent  preheating  furnaces,  there 
will  be  occasions  when  special  furnaces  will  be  required  for 
special  work,  and  in  view  of  this  fact  it  is  well  to  describe  the 
method  of  their  construction,  so  the  beginning  will  be  prepared 
when  the  occasion  comes. 

Building  a  Furnace: — The  article  to  be  heated  is  placed  on 
one  of  the  brick  topped  tables,  previously  described,  and  blocked 
up  with  brick.  Around  this  is  layed  a  course  of  brick  about 
six  or  eight  inches  away  from  the  article,  and  placed  end  to  end 
with  a  space  of  about  an  inch  and  a  half  between  them.  These 
spaces  are  for  air  draft  and  on  rare  occasions  it  may  be  neces- 


OPERATING   PLANTS  77 

sary  to  remove  a  brick  from  the  table  top,  to  admit  air  to  the 
interior.  On  top  of  this  course  are  piled  other  brick,  built  like 
a  wall  to  a  height  a  little  above  the  top  of  the  piece  to  be  welded. 

The  fuel  used  is  charcoal,  which  is  made  into  an  even  bed  all 
around  and  beneath  the  article.  Sheets  of  %  inch  asbestos  are 
layed  loosely  over  the  whole  furnace  and  the  charcoal  ignited 
through  the  holes  at  the  bottom  of  the  wall.  The  article  should 
be  arranged  so  that  the  part  to  be  welded  will  be  uppermost. 
Then  when  the  proper  temperature  has  l)een  attained,  an  open- 
ing can  be  made  through  the  asbestos  and  the  weld  finished 
without  removing  it  from  the  fire. 

Very  often  gas  burners  may  be  procured,  from  the  dealer, 
which  may  be  connected  with  the  acetylene  pipe  and  found  very 
convenient  for  preheating.  It  may  be  added  that  burners  de- 
signed for  city  gas  might  not  give  satisfaction  when  used  with 
acetylene.  If  one  intends  to  equip  with  preheating  burners,  it  is 
best  to  procure  burners  designed  for  the  gas  he  intends  to  use. 

Protecting  Apparatus: — Oxy-actylene  cutting  and  welding 
apparatus  are  not  classified  among  the  delicate  instruments  that 
are  liable  to  become  dearranged  and  out  of  order ;  but  they  de- 
serve and  require  care. 

They  are  designed  to  maintain  the  purity  of  the  gases.  To 
generate  cool  and  commercially  pure  acetylene  at  a  continually 
uniform  pressure  and  deliver  it  to  the  torch  in  the  same  con- 
dition. The  oxygen  is  reduced  from  an  extremely  high  pressure 
to  a  very  low  one  and  this  reduction  is  regulated  to  a  nicety.  The 
torch  mixes  these  gases  in  exact  proportions  and  burns  them  in  a 
small  but  exceedingly  hot  flame  where  the  gases  are  completely 
burned  and  none  escape  unconsumed.  The  manufacturers  of 
carbide,  from  which  the  acetylene  is  made,  exercise  the  greatest 
care  to  secure  and  use  none  but  the  most  pure  material ;  and 
the  manufacturers  of  oxygen  struggle  to  maintain  a  standard 
which  does  not  vary  three  tenths  of  one  percent,  from  perfectly 
pure  gas. 

The  manufacturers  go  to  all  this  trouble  because  they  un- 
derstand and  know  that  such  precautions  are  necessary  to  pro- 
duce the  best  results  in  the  welding  shop,  and  these  details  have 


78 


OXY-ACETYLENE  WELDING  AND  CtTTTJNG 


been  mentioned  here  to  admonish  the  welder  to  keep  his  apparatus 
clean  and  protect  it  from  harm,  for  it  is  not  reasonable  to  pre- 
sume that  good  work  may  be  done  when  the  appliances  are  kept 
in  a  careless  or  slovenly  manner. 

All  acetylene  generators  use  water  in  their  operation  and  for 
that  reason  they  must  be  protected  from  freezing.  The  quantity 
of  water  is  proportioned  to  the  amount  of  carbide  they  hold  and 
if  the  sediment  of  carbide  is  allowed  to  accumulate  in  the  bot- 
tom of  the  generator  it  reduces  the  water  capacity  and  causes 
other  irregularities  in  its  operation.  It  is  therefore  a  gool  rule 
to  never  fill  the  generator  with  fresh  carbide  until  after  the 
sludge  has  been  cleaned  from  the  bottom. 

Oxygen  is  stored  in  the  drums  under  very  high  pressure,  and 
if  this  pressure  is  suddenly  admitted  into  the  regulator,  it  is  liable 
to  injure  the  mechanism  of  the  regulator,  or  pressure  gauges.  The 
valve  on  top  of  the  oxygen  drum  should  therefore  be  opened 
slowly  and  left  wide  open  while  in  use. 


Fig.  25 
OPEN  THE  VALVK  ON  THK  OXYGKX  DKUM  SLOWLY 

Before  opening  this  valve  it  is  well  to  have  the  adjusting 
screw  on  the  regulator,  unscrewed  until  it  is  quite  free  and 
other  valves  closed. 


OPERATING   PLANTS 


79 


There  should  be  some  arrangement  to  securely  hold  the  oxy- 
gen drums  in  an  upright  position,  for  on  account  of  their  narrow 
base  they  may  be  easily  knocked  over  and  in  this  event  the  valve 
is  liable  to  be  injured. 


Fig.  26 
REMOVABLE  BASE  FOR  OXYGEN  DRUMS 

Some  manufacturers  provided  a  removable  base  which  may 
be  applied  to  oxygen  drums  to  prevent  their  upsetting.  This  ap- 
pliance allows  more  freedom  since  the  drum  is  not  confined  to 
any  particular  location  for  securing,  but  may  be  moved  about 
at  the  welder's  convenience. 

When  welding  over  a  preheating  fire,  where  the  article 
being  welded  is  imbeded  in  glowing  coals,  it  is  good  practice 
to  shield  the  torch  from  the  direct  heat  of  the  fire,  with  sheets  of 
asbestos.  The  first  time  the  torch  is  used  over  the  direct  flare 


SO  OXY-ACETYLENE  WELDING  AND  CUTTING 

of  the  fire  there  will  probably  be  no  perceptible  harm  done  to  it : 
but  a  repetition  of  this  practice  will,  in  time,  damage  it. 

Flashing  Back : — While  the  torch  is  overheated  in  this  way  it 
may  cause  temporary  annoyance  by  flashing  back.  This  annoy- 
ance may  be  removed  by  cooling  the  torch  in  water.  If  in  the 
course  of  the  work  it  is  desired  to  cool  the  torch  in  this  way, 
the  acetylene  should  be  completely  shut  off  and  the  flow  of  oxygen 
reduced  to  a  very  small  amount.  The  object  in  leaving  a  small 
flow  of  oxygen  is  to  prevent  water  entering  the  torch,  by  the 
eflux  of  gas  from  the  tip. 

The  propagation  of  the  oxy-acetylene  flame  is  about  330  feet 
a  second.  This  is  the  speed  at  which  a  flame  will  travel  through 
a  tube  containing  a  proper  mixture  of  oxygen  and  acetylene.  If 
the  gases  are  not  expelled  from  the  tip  of  the  torch  at  a  speed 
equal  to  or  greater  than  this,  the  flame  will  follow  back  through 
the  tip  into  the  chamber  where  the  gases  are  mixed  and  the  torch 
is  said  to  "Flash  Back."  While  the  gases  are  burning  in  the 
torch,  it  is  not  an  unusual  occurrence  to  see  long,  slender,  yellow 
streaks  of  flame  shoot  from  the  tip. 

If  the  torch  is  permitted  to  do  this  frequently,  or  to  continue 
burning  in  the  head  for  a  short  time,  it  damages  it  and  makes 
a  repetition  of  this  "Flashing  Back"  more  probable.  The  gases 
should  therefore  be  turned  off  immediately,  shutting  off  the 
oxygen  first. 

The  "Flashing  Back"  is  more  usually  caused  by  an  insufficient 
gas  pressure,  and  if  both  gases  are  turned  on  a  little  stronger,  and 
the  flame  readjusted  to  "neutral"  the  trouble  will  usually  cease ; 
but  insufficient  pressure  is  not  the  only  cause  which  may  effect 
"Flashing  Back."  If  the  torch  is  held  close  enough  to  the  work 
to  impede  the  flow  of  gas,  it  may  "Flash  Back;"  but  in  this  event, 
other  conditions  being  normal,  it  should  relight  when  it  is  with- 
drawn. If  the  tip  is  mutilated  or  roughened  inside  or  at  the 
end  it  may  produce  eddy-currents  that  will  cause  "Flashing 
Back;"  or  if  the  torch  is  held  too  close  to  melted  metal,  the  force 
of  the  gas  may  splash  the  metal  into  the  tip  and  produce  eddy- 
currents  that  will  cause  the  same  effect. 

Clean-  Hose : — Oxygen  will  not  burn.     In  the  presence  of  sub- 


OPERATING   PLANTS  81 

stances  containing  carbon  or  hydrogen  it  may  produce  flame ; 
but  it  is  the  carbon  or  hydrogen  which  burns,  and  the  oxygen 
supports  combustion. 

If  the  oxygen  hose  are  allowed  to  lay  around  on  a  floor 
that  is  soaked  with  kerosene  or  lubricating  oil,  the  oil  will  creep 
into  the  end  and  when  the  oxygen  is  turned  on,  the  hose  will  be 
liable  to  burn.  This  can  cause  no  further  damage  than  to  destroy 
the  hose,  for  if  the  oxygen  and  oxygen  drums  are  pure  and  clean, 
the  fire  can  not  enter  the  drum. 

Acetylene  is  a  carbonous  gas  and  may  leave  slight  deposits 
of  carbon  on  the  inside  of  the  acetylene  regulator  and  hose.  If 
the  acetylene  regulator  and  hose  are  used  in  the  oxygen  service 
they  are  liable  to  be  damaged  by  the  combustion  of  these  carbon 
deposits. 

Acetylene  In  Drums:  It  has  been  explained  under  the  chap- 
ter on  chemistry  that  acetylene  under  high  pressure  might  be- 
come dangerous  to  handle ;  but  dissolved  acetylene  in  drums, 
under  pressure,  has  extended  the  usefulness  of  the  gas  to  a  won- 
derful extent.  Acetone  is  a  hydro-carbon  and  the  product  of  dis- 
tillation of  wood.  It  is  a  colorless,  inflammable  fluid  and  is  much 
used  in  the  manufacture  of  chloroform,  iodoform,  and  other  medi- 
cal preparations.  This  long  known  but  rather  unfamiliar  fluid 
is  an  excellent  solvent  for  acetylene,  which  dissolves  in  it  as  freely 
as  sugar  does  in  water.  The  solubility  increases  with  pressure 
and  at  atmospheric  temperature  and  pressure  it  will  dissolve  24 
times  its  bulk  of  acetylene. 

This  phenomenon  is  utilized  to  the  great  advantage  of  the 
welder  by  dissolving  acetylene  in  drums  of  acetone.  The  drums 
supplied  are  33  inches  long  by  8  inches  in  diameter  and  contain 
100  feet  of  acetylene.  They  are  perfectly  safe  to  handle,  conven- 
ient for  portable  purposes,  give  no  trouble  by  freezing,  and  the 
gas  is  cool,  clean  and  dry.  Since  the  gas  issues  at  a  high  pres- 
sure, it  is  necessary  to  employ  a  regulator  to  bring  it  down  to  the 
proper  working  pressure. 

Portable  Acetylene  Drum  Plant: — A  small  but  very  conven- 
ient plant,  in  which  dissolved  acetylene  is  used,  is  shown  in 
figure  No.  27.  This  plant  consists  of  two  drums  of  oxygen  and 


82 


OXY-ACETYLENE  WELDING  AND  CUTTING 


two  of  acetylene  with  the  necessary  complement  of  torches, 
regulators  and  apparatus  to  make  up  a  complete  outfit.  One 
drum  of  each  gas  is  mounted  on  a  truck  for  convenience  in  mov- 
ing and  the  other  two  drums  are  used  for  storage. 

The  plant  is  always  ready  for  use  and  while  the  acetylene  costs 
a  little  more  than  in  the  generator  plants,  it  is  perfectly  practical 
for  the  man  who  does  only  a  moderate  amount  of  work. 

A  paragraph  on  connecting  and  operating  a  plant  of  this  de- 
scription will  not  be  out  of  place.  The  numbers  and  parts  re- 
ferred to  will  be  found  in  figure  No.  27. 


Fig.   27 
PORTABLE  PLANT  USING  DISSOLVED  ACETYLENE 


OPERATING   PLANTS  83 

Connect  the  oxygen  regulator  No.  I  to  the  valve  No.  2  on  the 
oxygen  drum.  Then  attach  the  black  oxygen  hose  to  the  regula- 
tor and  the  upper  valve  No.  3  on  the  torch.  Connect  the  acetylene 
regulator  No.  4  to  the  valve  No.  5  on  the  acetylene  drum.  Then 
attach  the  red  acetylene  hose  to  the  regulator  and  the  lower  valve 
on  the  torch.  Unscrew  the  regular  handles  Nos.  7  and  8  until 
they  do  not  bear  on  the  spring  inside.  This  will  close  the  regu- 
lators and  prevent  the  passage  of  gas  when  the  drum  valves  are 
opened.  Now  open  the  drum  valves  2  and  5,  and  the  torch  valves 
3  and  6.  Screw  in  the  handle  on  the  acetylene  regulator  until 
the  gas  begins  to  flow  and  adjust  the  flame,  as  will  be  described 
in  Chapter  No.  n.  The  apparatus  is  now  ready  to  use  for 
welding.  When  not  in  use  the  connections  may  be  left  intact 
with  the  valves  closed. 

Portable  Acetylene  Generator: — A  portable  generator  plant 
is  provided  for  welders  who  prefer  to  take  advantage  of  the 
saving  that  may  be  effected  by  generating  their  own  acetylene. 
The  plant  consists  of  a  generator  of  25  or  50  pounds  capacity 
mounted  on  a  four  wheeled  truck  with  two  oxygen  drums  and 
usually  provided  with  a  tool  box  for  supplies  and  small  apparatus. 
One  of  these  plants  is  shown  in  figure  No.  28.  It  will  be  connect- 
ed and  operated  much  the  same  as  the  plant  just  described  except 
that  the  acetylene  regulator  will  of  course  be  attached  to  the  gen- 
erator instead  as  directed  in  the  previous  paragraphs. 

Two  colored  hose  are  provided  to  distinguish  between  the 
oxygen  and  acetylene,  and  it  is  recommended  to  use  the  black 
hose  for  the  former  and  the  red  hose  for  the  latter. 

Regulating  the  Charge  For  Weldings — Purchasers  of  weld- 
ing outfits  are  immediately  confronted,  with  the  problem,  of  how 
to  adjust  their  charge  for  services,  to  conform  with  the  usual 
practice. 

To  give  explicit  directions  for  making  charges  would  be 
useless,  the  location  of  the  plant  with  references  to  neighboring 
towns,  shipping  facilities,  the  comparative  cost  of  labor  and 
commodities,  the  risk  attending  the  work,  the  urgency  of  the  de- 
mand, the  cost  of  a  new  piece  to  replace  the  broken  one  and  the 
cost  of  gases  including  freight  and  cartage,  are  all  factors  to  be 


84  OXY- ACETYLENE  WELDING  AND  CUTTING 

considered  in  determining  a  just  charge.  A  knowledge  of  how 
these  factors  enter  into  consideration  is  best  conveyed  to  the  be- 
ginner by  illustrations. 

As  a  rule  it  is  advisable  to  make  a  minimum  charge,  which 
may  range  between  75  cents  and  $1.00.  This,  however,  can  not 
be  rigidly  adhered  to. 


Fig.  28 
POETABLE  GENEKATOK  PLANT 

If  the  welder  has  his  torch  lit  and  can  conveniently  leave  his 
work  for  a  few  minutes  to  weld  a  job  of  comparative  insignifi- 
cance, a  charge  of  5oc  might  be  both  just  and  profitable,  but  if 
the  weld  is  to  be  made  on  the  knotter  of  a  binder,  the  charge  could 
justly  be  proportionately  higher.  For  instance  if  the  selling  price 
of  the  piece  is  $5.00  and  the  express  charges  4oc,  the  actual  cost 
of  a  new  piece  would  be  $5.40.  The  time  required  to  get  this 
piece  from  the  dealer,  might  be  two  days,  during,  which  time  the 
binder  would  be  out  of  commission.  If  in  welding  the  old  piece, 
the  welder  uses  75c  worth  of  gas  and  one  hour's  time  at  35c  it 


OPERATING   PLANTS  85 

would  actually  cost  him  $1.10  to  do  the  work  but  in  this  instance 
he  would  be  amply  justified  in  a  charge  of  $4.00. 

To  determine  the  actual  cost  of  work  one  would  proceed  as 
follows.  Two  drums,  one  hundred  feet  each  at  2c  per  foot,  would 
cost  $8.00,  to  this  would  be  added  freight  and  cartage,  which 
might  come  to  $1.00,  making  a  total  cost  of  $9.00  for  400  feet  or 
2l/4  cents  per  foot.  The  acetylene,  if  purchased  in  drums,  would 
be  calculated  the  same  way ;  but  if  it  is  generated  in  the  shop,  one 
would  consider  the  cost  of  carbide.  One  hundred  pounds  of  car- 
bide at  3^[c  comes  to  $3.75  plus  4Oc  for  freight  and  cartage 
makes  a  total  of  $4.15  per  hundred  pounds  carbide.  This  will 
generate  450  feet  of  acetylene  which  puts  the  cost  of  acetylene  at 
about  9-10  of  a  cent  per  foot. 

From  the  table,  in  the  back  of  this  book,  may  be  learned  the 
amount  of  each  gas  the  various  sized  tips,  used  during  one  hour 
of  continuous  burning.  To  find  the  cost  of  gas,  used  on  a  job, 
would  simply  require  multiplying  the  quantity  used  per  hour  by 
the  number  of  hours  in  use,  and  that,  by  the  cost  per  foot. 

To  do  a  certain  job  of  welding,  we  will  suppose  it  required 
3  hours  time,  90  feet  of  oxygen,  87  feet  of  acetylene,  10  pounds  of 
charcoal,  and  one  pound  of  welding  rod,  and  it  is  desired  to  figure 
the  cost.  A  typical  procedure  would  be  as  follows : 

3  hours  time,  at  35c    $  1.05 

90  ft.  oxygen,  at  2J/±c 2.02 

87  ft.  acetylene,  at   ic   : 87 


$  3-94 
Double  for  over  head  charges 2 


$  7.88 

i   Ib.  welding  rod,  at  IDC 10 

10  Ibs.  charcoal,  at  ic. .  10 


Total  cost   $  8.08 

50%  profit  on  work 4.04 

Charges  for  work $12.12 

The  purposes  for  doubling  the  cost  of  labor  and  gases  for 


86  OXY-ACETYLEXE  WELDING  AXD  CUTTING 

overhead  charges,  is  to  cover  the  cost  of  maintaining  and  operat- 
ing the  shop,  including  rent,  heat,  light,  insurance,  bad  ac- 
counts, etc. 


OXYGEN  ACETYLENE  WELDING  CO. 
TIME  CARD 

Job.  No 

Date     Tag  No 

Workman    Tag  No 

Tag  No 

Tag  No 

Hrs.  Labor 

Hrs.  Overtime | 

Tip   No Hrs | 

Tip   No Hrs | 

Hrs.  Oil  Torch | 

Lbs.  Charcoal I 

Lbs.  Asbestos    | 

Lbs.  Asbestos  Cement   ! 

Lbs.  Cast   Iron    I 

Lbs.  Steel | 

Lbs.  Aluminum    | 

Lbs.  Bronze .  .  | 

Lbs.  Copper j 

Misc.   Material 


Description  of  work 


Fig.  29 
CONVENIENT  TIME  CAED  FOR  WELDING  SHOPS 


87 

CHAPTER  X. 
WELDING  RODS  AND  FLUXES. 

The  Theory  of  Fluxes: — Fluxes  are  used  to  clean  the  sur- 
faces of  the  metals,  to  remove  or  prevent  the  accumulation  of 
impurities  by  uniting-  with  them  before  they  combine  with  the 
metals,  and  sometimes,  to  lower  the  melting-  temperature.  The 
action  is  purely  a  chemical  one  and  the  task  of  preparing  or  pre- 
paring or  prescribing  suitable  fluxes  for  the  various  metals, 
should  only  be  undertaken  by  one  who  is  thoroughly  familiar  with 
their  chemical  reactions. 

The  physical  and  chemical  properties  of  the  various  metals 
are  so  different  that  a  flux  which  would  be  suitable  for  welding 
one  material  would  be  ruinous  to  another.  To  illustrate,  phos- 
phorus contained  in  copper  alloys,  increases  their  strength  and 
toughness ;  but  one  tenth  of  one  per  cent  in  steel  causes  it  to  be 
very  brittle.  Phosphorus  has  a  great  affinity  for  oxygen  and 
when  incorporated  in  melted  copper,  it  will  unite  with  the  oxy- 
gen which  the  copper  absorbs,  and  burn  out  taking  the  oxygen 
with  it ;  but  with  iron,  for  which  phosphorus  has  a  greater  affinity, 
this  is  different ;  when  phosphorus  is  incorporated  in  melted  iron 
it  does  not  combine  with  oxygen,  but  remains  in  the  iron  and 
makes  it  brittle. 

The  Theoretical  flux  for  each  of  the  metals  would  be  a  sub- 
stance that  would  combine  with  the  gaseous  impurities  which  are 
brought  in  contact  with  the  melted  metal,  and  after  combining, 
will  be  liberated  and  pass  off  as  a  gas,  or  form  a  slag  that  will 
float  on  the  surface.  Since  the  service  of  a  flux  is  in  chemically 
uniting  with  objectionable  impurities  and  removing  them,  and 
since  this  chemical  union  can  only  occur  in  a  definite  proportion,  it 
follows,  that  if  more  flux  is  used  than  will  chemically  unite  with 
the  element  to  be  removed,  it  will  be  free  to  unite  with  something 
else  and  become  a  new  objection.  For  this  reason  fluxes  should 
be  used  strictly  in  accordance  with  the  instructions  given  by  the 
manufacturers. 

The  gaseous  impurity,  usually  combated  by  fluxes  is  oxygen; 
but  in  some  metals,  such  as,  copper,  bronze,  and  aluminum, 
there  are  other  gases  that  may  be  absorbed  unless  their  absorbtion 
is  prevented  by  the  presence  of  a  suitable  flux.  In  instances  of 


88  OXY-ACETYLEXE  WELDING  AND  CUTTING 

this  kind  the  formula  for  the  fluxes,  are  sometimes  quite  compli- 
cated and  to  avoid  the  excessive  use  of  certain  chemicals  they  are 
frequently  incorporated  in  the  welding  rod.  Then  by  using  these 
rods  with  the  fluxes  designed  for  them,  the  gases  are  completely 
absorbed  and  eliminated. 

To  weld  ivrought  iron,  steel  castings,  steel  plates  and  forg- 
ings,  no  flux  should  be  required;  but  a  special  steel  welding  rod 
is  furnished  in  which  the  metaloids  are  combined  in  the  right 
proportion  to  give  the  best  results. 

Cast  Iron  requires  a  flux  to  destroy  the  oxide,  which  is  less 
fusible  than  the  metal,  and  which  interposes  itself  in  the  welds  and 
prevents  the  perfect  joining  of  the  molten  metal.  The  action  of 
the  flux  is  to  lower  the  melting  temperature  of  the  iron  oxide, 
which  will  then  float  to  the  surface  where  it  may  be  removed. 

The  welding  rods  should  be  selected  according  to  their  sili- 
con content.  The  right  proportions  of  silicon  tend  to  eliminate 
the  oxide  from  the  iron. 

Coppers — When  copper  and  the  copper  alloys  are  melted 
they  absorb  oxygen,  hydrogen,  and  carbon  dioxide  gases  and  to 
combat  these  gases  is  a  problem  that  has  not  been  solved  until 
recently.  The  first  attempts  to  absorb  these  gases  into  flux  re- 
sulted in  changing  the  texture  of  the  weld ;  but  today  the  manu- 
facturers are  supplying  a  flux  to  be  used  with  a  special  welding 
rod,  and  the  results  obtained  with  them  are  eminently  satisfac- 
tory. 

It  follows  from  what  we  have  just  explained,  that  the  manu- 
facture of  welding  materials  containing  deoxidizing  elements,  is 
extremely  delicate,  and  necessitates  rigorous  supervision  and  con- 
trol. 

Welders  who  use  the  oxy-acetylene  process  in  manufacturing 
and  repairing,  are  by  no  means  disposed  to  analyze  or  examine 
micrographically,  the  materials  they  are  putting  into  their 
welds,  and  since  these  precautions  are  necessary  to  the  production 
of  reputable  welding  materials,  it  is  well  to  shoulder  the  respon- 
sibility on  a  trustworthy  manufacturer  whose  success  depends  on 
your  success. 

'The  selection  of  rods  and  fluxes  for  the  different  metals  will 
be  treated  fully  under  the  subject  of  welding. 


39 
CHAPTER  XI. 

GENERAL  NOTES  ON  WELDING. 

Time  used  in  preparing  for  the  weld  is  well  spent.  In  a  feu- 
days,  a  welder  can  acquire  sufficient  skill  in  handling  the  torch,  to 
perform  a  fairly  good  weld,  under  favorable  circumstances;  but 
to  do  equally  good  work  under  any  circumstance,  requires 
thought,  study  and  experience. 

The  primary  object  is  to  secure  a  weld  that  will  be  homo- 
genous in  texture,  free  from  blow-holes,  hard  spots  or  scale,  void 
of  internal  strains,  and  to  leave  the  piece  free  from  distortion. 
The  first  three  features  mentioned  are  obtained  in  the  actual  per- 
formance of  welding,  and  will  be  treated  fully  in  a  later  para- 
graph, but  to  leave  work,  void  of  strains  and  distortion  requires 
preparation  in  the  way  of  preheating. 

Cleaning: — It  is  unnecessary  to  spend  much  time  in  cleaning, 
scraping,  or  brightening  the  part  to  be  welded,  as  would  be  re- 
quired for  brazing  or  soldering.  The  only  requisite  in  this  line 
is  to  remove  the  mud  or  grease  by  wiping.  Other  impurities  burn 
or  are  melted  and  float  to  the  surface  where  they  may  be  scraped 
off  with  a  rod. 

Beveling  ? — If  the  piece  to  be  welded  is  thicker  than  */$  of  an 
inch,  some  time  and  advantage  may  be  gained  by  beveling  the 
edges,  to  enable  the  flame  to  enter  between  them,  and  the  weld 
started  at  the  bottom  and  built  up.  In  pieces  thinner  than  >£  of 
an  inch,  it  is  only  necessary  to  separate  the  edges  about  1-16  of  an 
inch,  to  obtain  the  same  advantage.  If  the  pieces  are  very  thin, 
like  sheet  iron  of  14  gauge  and  lighter,  they  are  liable  to  give 
some  trouble  by  warping  and  buckling,  and  as  the  welding  con- 
tinues there  may  be  a  tendency  for  them  to  overlap  each  other. 
If  this  overlapping  is  permitted  it  will  not  only  make  the  operation 
of  welding  more  difficult,  but  it  will  destroy  the  intended  shape 
of  the  article  being  welded.  The  operator  should,  therefore,  care- 
fully watch  that  the  edges  do  not  overlap,  and  if  they  can  be  bent 
up  at  right  angles  to  a  height  of  1-16  of  an  inch  it  will  make  the 
work  much  easier.  The  bent  up  edges  are  melted  and  furnish 
welding  material. 


90  OXY- ACETYLENE  WELDING  AND  GUTTING 

The  amount  of  advantage  gained  in  beveling,  depends  on  the 
thickness  of  the  piece,  and  the  method  of  beveling.  The  object 
being  to  enable  the  operator  to  melt  the  material  in  the  bottom  and 
sides  of  the  fracture  and  fill  the  gap  with  new  material  melted 
from  the  end  of  the  welding  rod.  To  secure  a  thorough  and 
strong  job,  it  is  easily  understood  that  this  process  must  include 
the  whole  fractured  surface,  otherwise  there  will  be  a  portion  un- 
welded,  and  unless  the  edges  are  cut  away  or  beveled,  it  will  be 
necessary  to  melt  the  material  and  blow  or  scrape  it  out,  to  be 
certain  that  the  welding  includes  the  entire  fractured  surface. 
Fig.  34  and  35  show  the  method  of  beveling  pieces  y%  inch  to  *4 
inch  thick. 


Figures  34  and  35 
PRACTICAL  METHOD  OF  BEVELING  THIN  PIECES 

In  work  of  this  kind  it  is  practical  to  bevel  one  side  only ;  but 
in  thicker  material,  if  access  can  be  had  to  the  reverse  side,  a 
saving  may  be  obtained  by  beveling  both  sides  as  shown  in  Fig. 

36. 

This  can  not  always  be  done,  for  the  reverse  side  may  not  be 
accessible ;  but  the  work  and  expense  is  reduced  about  one-half  and 
there  is  greater  assurance  of  a  thorough  weld,  when  the  work  is 
done  from  both  sides.  The  beginner  is  very  liable  to  sacrifice 
good  work  for  neatness  and  appearance.  It  is  much  easier  to  do 
a  neat  looking  job  by  simply  welding  on  the  surface ;  but  this 
practice  is  positively  to  be  condemned,  and  although  a  deep  weld 
may  look  scattered  and  irregular  the  beginner  should  train  him- 
self until  deep  welding  becomes  instinctive  or  habitual. 


GENERAL  NOTES  ON  WELDING 


Fig.  36 
METHOD   OF   BEVELING   THICK   PIECES 

A  weld  which  is  made  from  both  sides  will  look  neater  because 
the  breadth  of  the  fused  surface  will  be  narrower,  and  it  can  be 
more  quickly  finished,  because  the  area  of  the  cross  section 
through  the  weld  is  only  half  as  great,  consequently  there  is  only 
half  as  much  metal  to  melt  and  fill  in.  This  is  more  clearly  illus- 
trated in  Figs.  37  and  38. 


Figures  37  and  38 
ILLUSTRATING  THE  ECONOMY  OF  BEVELING  ON  BOTH  SIDES 

in  which  the  area  is  divided  into  triangles  having  equal  area. 
This  illustration  is  self  explanatory,  it  being  necessary  to  merely 
count  the  nnmber  of  triangles  in  each  figure,  to  ascertain  the 
comparative  areas. 

Precautions  Regarding  Expansion : — The  phenomenon  of  ex- 
pansion is  explained  on  page  32  under  the  chapter  on  physics, 
and  it  is  here  proposed  to  explain  to  the  welder,  how  this  phe- 


92 


OX Y- ACETYLENE  WELDING  AND  CUTTING 


nomenon  may  effect  his  success  or  defeat  according  to  his  under- 
standing, and  preparation  to  provide  for  it. 

When  metal  is  heated  it  will  expand  and  there  is  no  evading 
it.  Sometimes  trouble  occurs  when  expansion  is  taking  place. 
At  other  times  it  does  not  develop  until  after  the  metal  com- 
mences to  shrink,  or  resume  its  original  proportions.  The  re- 
sult of  expansion  and  contraction  often  produces  the  most  unex- 
pected effects,  and  the  welder  is  admonished  to  give  this  subject 
much  earnest  thought.  No  text  book  can  tell  him  what  may 
happen  or  what  to  do  on  every  occasion  that  may  develop  during 
his  welding  career;  these  are  things  that  must  be  studied  out  by 
himself,  and  his  ultimate  success  depends  as  much  on  his  ability 
to  overcome  the  effects  of  expansion  as  on  his  ability  to  handle 
the  torch.  So  do  not  pass  this  subject  until  you  are  thoroughly 
determined  to  observe,  study  and  solve  the  capers  that  expansion 
will  play  with  you  during  your  earlier  efforts.  Sometimes  the 
effect  of  expansion  can  be  ignored,  and  the  welder  will  soon 
learn  by  experience,  when  this  will  be  true.  A  good  illustration 
of  this  is  in  figures  39  and  40. 


Figures  39  and  40 
EFFECTS  OF  EXPANSION  AND  CONTRACTION 

In  Fig.  39,  no  bad  effects  of  expansion  are  to  be  feared  be- 
cause the  ends  are  free  to  move  and  extend  or  withdraw.  On 
the  contrary  in  Fig.  40  the  same  bar  having  the  same  break,  is 
the  center  member  in  a  two  panel  frame.  What  will  be  the  effect 


GENERAL  NOTES  ON  WELDING  93 

of  expansion  in  this  case?  As  the  metal  in  the  vicinity  of  the 
weld  becomes  heated  it  will  expand.  The  ends  being  a  part  of 
the  frame  at  3  and  4  will  be  held  in  their  normal  position;  but 
the  melted  portion  surrounding  the  weld  will  offer  no  resistance, 
and  the  expansion  will  push  the  melted  ends  closer  together  in 
the  weld.  When  the  job  is  finished,  and  the  metal  begins  to 
cool  off,  shrinkage  takes  place  and  the  center  bar  shortens.  If 
the  metal  is  elastic  or  ductile  the  shrinkage  may  not  cause  a 
break,  but  will  cause  a  strain  or  deformation  of  the  frame.  This 
would  probably  be  the  case  with  mild  steel;  but  with  cast  iron, 
it  would  likely  cause  a  break  in  the  hottest  place,  which  would  be 
in  the  newly  welded  portion.  Neglect  to  provide  for  expansion 
would  therefore  cause  failure. 

Copper,  aluminum,  cast  iron,  and  those  metals  that  are  weak- 
est when  hot,  will  usually  break  in  the  weld. 

On  reflection,  it  will  be  observed  that,  to  make  a  success 
of  this  job,  it  is  only  necessary  to  preheat  the  portion  of  the 
frame,  indicated  at  I  and  2,  then  on  cooling  the  shrinkage  will 
be  equal  in  each  of  the  parallel  bars,  and  no  break  or  distortion 
will  result. 

If  it  is  impossible  to  heat  the  frame,  as  described  above,  othei 
methods  are  at  the  disposal  of  the  welder ;  for  example,  a  slight 
spreading  of  the  two  bars  3  and  4,  to  the  position  indicated  by 
the  dotted  lines.  This  may  be  done  with  keys,  wedges,  or  jack- 
screws,  and  the  effect  is  to  separate  or  spread  the  fracture. 
While  making  the  weld,  expansion  takes  place,  as  described  be- 
fore; but  when  the  weld  is  finished  and  shrinkage  commences 
the  wedges  or  screws  are  removed,  and  as  the  center  bar  shortens, 
the  sides  gradually  resume  their  former  position,  and  the  frame 
is  void  of  strains  or  fracture. 

Another  method,  which  is  not  especially  recommended  ex- 
cept on  rare  occasions,  is  to  cut  the  frame  at  5,  then  weld  the 
fracture  and  the  cut  will  accommodate  the  expansion  by  spread- 
ing, then  after  the  center  bar  has  been  welded  and  shrunken, 
the  cut  in  the  corner  can  be  welded,  where  the  effects  of  ex- 
pansion and  contraction  need  not  be  feared. 

There  has  recently  come  into  use,  a  method  of  restricting 
the  expansion  to  a  very  limited  portion,  resulting  in  the  ex- 


94  OXY-ACETYLENE  WELDING  AND  CUTTJNG 

pansion  being  so  slight  that  it  may  be  ignored.  This  is  done 
by  allowing  the  portion  immediately  surrounding  the  weld,  to 
attain  the  required  temperature;  but  preventing  the  heat  spread- 
ing, which  of  course  will  reduce  the  expansion,  by  cooling  the 
surrounding  portion  with  water. 

If  restricting  the  amount  and  extent  of  expansion  is  all  that 
is  to  be  desired,  this  method  might  give  satisfactory  results ; 
but  there  are  other  causes  that  may  produce  failure.  One  of 
these  is  chilling  the  metal.  For  reasons  that  will  be  explained 
later  it  is  desirable  to  have  the  weld  and  surrounding  metal 
as  hot  as  it  can  be  made  without  changing  its  shape,  or  texture, 
and  if  the  cooling  method  is  used  to  eliminate  expansion,  the 
heat  of  the  portion  being  welded,  will  be  conducted  away,  and 
it  will  be  impossible  to  maintain  a  temperature  that  will  give 
the  best  results. 

The  Economy  of  Preheating: — Preheating  is  essential  as  an 
economic  measure.  To  properly  execute  a  weld,  the  sides  and 
bottom  of  the  fracture  must  be  melted,  and  if  the  metal  is  cold 
it  will  require  more  of  the  welder's  time,  and  more  gas  to  bring 
it  up  to  the  melting  temperature,  than  if  it  had  been  previously 
heated  with  a  cheaper  fuel  in  a  manner  that  did  not  require  the 
constant  attention  of  the  operator.  Therefore,  to  obtain  the 
greatest  measure  of  economy,  the  piece  to  be  welded  should  be 
placed  in  a  preheating  furnace,  and  allowed  to  heat  up  while 
the  welder  is  doing  something  else. 

Preheating  to  Eliminate  Defects  in  the  Weld: — It  has  been 
explained  under  the  chapter  on  metallurgy  called  "Metals  and 
Their  Properties,"  that,  when  melted  cast  iron  or  high  carbon 
steel  comes  in  contact  with  a  cold  metallic  surface,  it  chills  and 
becomes  so  hard  that  it  cannot  be  machined  or  filed.  It  is  not 
an  uncommon  thing  to  find  hard  spots  in  a  cast  iron  weld,  which 
have  been  caused  in  this  way. 

Cast  iron  contains  more  impurities  than  any  of  the  ferrous 
group,  and  when  it  is  melted,  these  impurities  form  a  gas  and, 
if  the  metal  is  sufficiently  fluid,  they  will  float  to  the  surface  in 
bubbles  and  be  liberated;  but  if  the  melted  metal  is  not  per- 
fectly fluid,  these  bubbles  will  remain  in  the  bath  and  show  blow 
holes  in  the  weld. 


GENERAL  NOTES  ON  WELPINii  93 

In  heavy  sections  of  cast  iron  that  have  not  been  preheated, 
the  melted  metal  is  chilled  so  rapidly  by  the  surrounding-  cold 
portion,  that  it  cannot  be  kept  sufficiently  fluid  for  these  gas 
bubbles  to  raise. 

Considering  the  foregoing  it  may  be  said,  that  the  practice 
of  preheating  cannot  well  be  eliminated. 

How  and  Where  to  Preheat: — An  article  like  an  automobile 
cylinder  or  motor  frame  should  be  heated  throughout,  so  that 
the  whole  piece  will  be  hot  and  expand  in  all  directions  alike. 
This  is  also  true  of  any  other  small  intricate  piece  that  may 
become  badly  distorted  or  broken  by  unequal  expansion ;  but  in 
the  case  of  a  large  flywheel  or  gear,  with  one  or  two  broken 
spokes,  it  would  be  cumbersome,  expensive  and  unnecessary  to 
preheat  the  whole  wheel. 

Large  articles  of  this  nature  are  only  preheated  in  a  portion 
which  must  be  selected  according  to  the  location  of  the  break. 
This  portion  will  usually  include  the  hub  and  a  little  over  one- 
half  of  the  rim,  including  the  broken  portion.  The  preheating 
furnace  for  this  kind  of  work  will  be  a  temporary  affair  built 
of  loosely  piled  brick,  with  an  asbestos  covering.  One  side  is 
semi-circular,  and  follows  the  contour  of  the  wheel,  and  the  other 
side  is  straight,  fitting  around  the  spokes  and  rim.  The  arrange- 
ment of  air  drafts  must  accommodate  the  nature  of  the  work. 

Adjusting  the  Flame : — One  of  the  first  things  the  welder  will 
note,  is  the  peculiar  appearance  of  the  flame  issuing  from  the 
tip  of  his  torch.  When  this  is  in  normal  working  condition  there 
will  be  an  inner  white  flame  of  dazzling  brightness,  surrounded 
by  an  outer  flame  of  a  pale  bluish  tinge,  with  a  wide  yellow 
border.  When  this  inner  flame  is  at  the  maximum  size  attainable, 
and  has  a  clear  distinct  outline,  the  flame  is  said  to  be  neutral. 
That  is,  it  will  have  neither  an  oxidizing  or  carbonizing  effect 
on  the  weld.  With  very  few  exceptions,  this  is  the  kind  of  flame 
that  should  be  obtained  before  starting  to  weld.  Manipulating 
the  valves  to  produce  this  kind  of  flame  is  called  adjusting  the 
torch.  The  method  of  procedure,  to  attain  this  adjustment,  is 
described  as  follows: 

After  connecting  the  torch  and  regulators  as  described  in 
chapter  8,  the  operator  will  see  that  all  valves  are  open  except 


96  OXY-ACETYLENE  WELDING  AND  CUTTING 

those  in  the  regulators,  these  will  be  closed  by  unscrewing  the 
handle  until  it  is  quite  free  and  does  not  bear  on  the  springs 
within.  Starting  from  this  position  the  operator  will  screw  in 
the  handle  on  the  Acetylene  regulator  until  the  gas  begins  to 
flow,  and  then  ignite  it.  Continue  to  screw  in  the  valve  handle, 
until  the  base  of  the  flame  appears  to  leave  the  torch  and  stand 
away  about  an  eighth  of  an  inch. 

The  acetylene  flame  is  now  a  large,  flaring,  smoky,  irregular 
shaped  mass :  but  screw  in  the  handle  on  the  o.vygcn  regulator, 
and  the  flame  will  commence  to  assume  definite  size  and  propor- 
tion. Continue  to  slowly  open  this  valve  and  there  will  appear 
an  inner  white  flame  that  blends  with  a  thin  feathery  edge  into 
a  pale  blue  outer  flame. 

As  the  oxygen  supply  is  increased,  this  inner  white  flame 
becomes  smaller  and  the  outline  more  distinct  and,  when  this 
thin  feathery  edge  is  entirely  gone,  the  inner  flame  will  be  about 
three  times  longer  than  in  diameter,  and  have  a  distinct  outline. 
This  is  a  neutral  flame,  and  is  the  proper  flame  for  welding. 

Handling  the  Torch : — Having  the  edges  of  the  metal  beveled 
as  described  before,  and  placed  parallel,  the  flame  of  the  torch 
is  directed  into  the  V  shaped  groove  formed  by  the  bevel.  The 
metal  on.  the  sides  and  bottom  of  the  groove  is  melted  until  it 
is  quite  fluid,  then  the  end  of  the  welding  rod  is  brought  under 
the  flame  and  when  it  commences  to  melt  it  is  submerged  in  the 
metal  melted  from  the  sides  of  the  groove. 

The  flame  and  welding  rod  are  kept  continually  in  motion. 
the  rod  following  close  behind  the  flame,  repeatedly  dodging  in 
and  out  from  under  it  with  a  little  circular  motion;  but  always 
submerged  in  the  melted  metal  and  always  hot  enough  to  be 
continuously  melting  and  feeding  the  weld  with  new  material. 

The  torch  will  be  advanced  along  the  line  of  the  weld  just  as 
fast  as  the  sides  and  bottom  will  melt,  and  become  thoroughly 
fluid,  while  the  frequency  of  the  circular  movements  of  the  rod 
and  the  length  of  time  it  remains  under  the  flame,  will  be  timed 
to  fill  the  weld  as  fast  as  the  torch  advances.  The  flame  and 
rod  should  always  be  together. 

1  At  first  the  welder  will  be  bothered  by  having  his  welding 
rod  freeze  to  the  weld,  which  will  have  to  be  melted  loose  again 


GENERAL  NOTES  OX  WELDING  07 

with  the  torch  ;  but  he  should  be  undaunted  by  these  little  events 
for  they  only  serve  to  remind  him  that  his  welding  rod  must 
always  be  melting  hot  and  submerged  in  melted  metal. 

It  takes  practice  to  acquire  the  knack  of  having  the  torch 
and  rod  continually  in  motion  describing  little  circles,  keeping 
them  close  together,  regulating  the  melting  rate  of  the  rod  to 
fill  the  weld  as  fast  as  the  sides  of  the  groove  are  melted  and 
become  fit  to  receive  new  material ;  but  the  knack  is  acquired 
with  only  a  few  days  of  persistent  effort. 

The  melting  of  the  welding  rod  and  the  edges  of  the  weld 
must  take  place  at  the  same  time,  and  the  rod  stirred  in  the  puddle 
of  melted  metal,  to  make  the  two  metals  alloy  immediately  wit'' 
each  other. 

If  the  rod  flows  between  the  edges  of  the  weld  before  the_ 
are  melted,  the  weld  will  be  bad. 

The  melting  rod  should  never  fall  in  drops  on  the  weld. 


Fig.  41 
THE    MELTING   ROD   SHOULD   NOT   DR1/P   INTO   THK   WHLD. 

The  torch  should  be  held  so  that  the  end  of  the  white  flame 
is  l/%  to  ys  of  an  inch  away  from  the  work,  the  distance  being 
proportional  to  the  size  of  the  tip  and  the  nature  of  the  work. 
For  a  medium  sized  tip  a  good  average  distance  would  be  J4  of 
an  inch.  Extreme  care  must  be  taken  to  not  permit  the  end  of 
the  tip  to  touch  the  melted  metal,  or  to  allow  the  melted  metal  to 
splash  into  the  tip. 


98 


OX Y- ACETYLENE  WELDING  AND  CUTTING 


Movements  of  the  Torch: — An  advantage  may  be  gained  by 
giving  the  torch  a  slight  circular  movement  to  direct  the  flame 
relatively  against  one  side  of  the  weld,  back  onto  the  welding 
rod,  over  to  the  other  side  of  the  weld,  then  forward  onto  the 
unmelted  portion  and  thus  continue  in  a  series  of  little  circles, 
of  uniform  size  and  regular  frequency.  The  diameter  of  the 
circles  should  be  nearly  equal  to  the  breadth  of  the  weld. 


Fig.  42 

CIRCULAR  MOVEMENT  OF  TORCH  FOR  WORK  OF  MEDIUM 
THICKNESS 


For  welds  of  greater  thickness  a  side  to  side  movement  may 
give  better  results.  The  amount  of  the  movement  correspond- 
ing with  the  breadth  of  the  weld,  and  regulated  in  time  to  the 
melting  of  the  sides.  These  movements  are  however  only  sug- 
gestions, and  the  welder  must  decide  for  himself  what  course 
he  will  pursue. 


GENERAL  NOTES  ON  WELDING 


99 


Fig.  43 
SIDE  TO  SIDE  MOVEMENT  OF  THE  TORCH  FOR  HEAVIER  WELDS 

There  are  certainly  manipulations  to  be  learned,  but  they 
are  relatively  easy  to  acquire,  and  are  better  obtained  by  practice 
than  by  reading. 

The  beginner  usually  does  not  melt  enough  and  the  weld 
lacks  penetration,  or  he  melts  too  much,  and  so  makes  holes. 
It  is  evidently  necessary  to  find  a  happy  medium,  and  above  all 
to  work  regularly. 

Filling  in  Holes: — Holes  are  particularly  despairing  to  the 
beginner,  because  in  trying  to  mend  them,  he  usually  sees  them 
enlarge.  A  few  instructions  on  filling  these  holes  will  be  appro- 
priate here.  The  flame  should  be  inclined  until  it  is  almost 
parallel  with  the  surface  of  the  work  and  directed  against  the 
edge  of  the  material.  As  soon  as  the  metal  begins  to  get  plastic, 
a  little  metal  is  welded  to  the  edge,  from  the  welding  rod.  Con- 
tinue this  process  until  the  hole  is  filled.  The  principal  difficulty 
encountered  in  this  work  is  to  regulate  the  heat  so  that  it  will 
not  melt  the  edges  away  or  cause  the  welding  rod  to  drip  through 
the  opening. 


100  OXY- ACETYLENE   WELDING  AND  CUTTING 


Fig.   44 
POSITION  OF  TORCH  FOR  FILLING  HOLES 

Defects  of  Welds: — During  the  process  of  welding  there  are 
several  defects  that  may  develop  and  to  avoid  them  the  welder 
is  admonished  to  be  constantly  alert  to  the  causes  that  may  pro- 
duce them. 

The  first,  is  lack  of  penetration.  This  more  frequently  takes 
place  when  the  edges  of  the  weld  are  not  beveled;  the  heat  has 
not  been  sufficient  to  melt  through  the  metal,  and  the  original 
crack  shows  on  the  reverse  side.  This  not  only  effects  the  solidity 
of  the  weld,  but  affords  a  starting  point  for  a  new  break. 

To  'avoid  this  defect,  one  must  not  go  to  the  other  extreme 
and  melt  holes  through  the  piece,  for  these  holes  cause  loss  of 
heat  and  time,  and  assist  oxidation. 

Next  there  is  adhesion.  This  very  significant  term  is  difficult 
to  explain.  One  obtains  adhesion  in  different  ways,  either  by 
not  sufficiently  melting  the  edge  of  the  weld,  or  by  doing  so  un- 
equally. It  may  also  be  done  by  flowing  melted  metal  onto  parts 
that  have  not  been  previously  melted,  or  have  cooled  off,  and 
again  by  interposition  of  oxide  in  the  bath. 

Welders  .should  exercise  constant  care  to  avoid  ^adhesion ' ' 
fof-4t-ts-»et  rare  to  find  this  defect  in  welds  made  by  experienced 
Melted  metal  flowing  from  the  edges  of  .the  weld 


GENERAL  NOTES  ON  WELDING  101 

into  the  bottom.,  will  cause  the  same  defect,  if  the  bottom  i>  not 
melted. 

There  are  sometimes  bad  joints  due  to  the  interposition  of 
a  layer  of  oxide  between  the  old  and  new  metal;  this  is  gen- 
erally due  to  piling  melted  metal  on  metal  that  has  solidified, 
or  to  lack  of  liquefaction  in  the  molten  bath. 

Blow  holes  frequently  form  in  the  weld  and  the  strength 
of  the  joint  suffers  accordingly.  These  blow  holes  may  be  due 
to  lack  of  preheating,  to  absorption  of  gases,  or  to  blowing  air 
into  the  melted  metal  with  the  torch.  The  elimination  of  the 
first  two  defects  will  be  treated  under  the  subject  of  welding  the 
different  metals. 

We  must  mention  lastly  that  welds  are  sometimes  insufficient- 
ly filled.  The  level  of  the  weld  does  not  reach  the  surface  of 
the  piece.  Such  defects  are  attributed  entirely  to  carelessness. 

Welding  Wrought  Iron  and  Mild  Steel'. — Wrought  iron  and 
mild  steel  are  the  easiest  metals  to  weld  by  the  autogenous  proc- 
ess. They  require  no  flux  to  absorb  oxides  or  other  impurities. 

A  steel  welding  rod  is  used  and  by  following  the  instruc- 
tions given  in  the  preceding  paragraphs  of  this  chapter,  the 
welder  is  provided  with  all  the  instructions  he  may  require.  The 
only  other  thing  needed  is  practice. 

Welding  Cast  Iron  : — When  everything  is  taken  into  con- 
sideration, the  difficulties  to  be  overcome  in  welding  cast  iron, 
are  neither  numerous  or  insurmountable,  as  a  matter  of  fact 
when  cast  iron  is  properly  welded  the  joint  is  stronger  than 
the  original  piece.  This  is  generally  due  to  the  superior  quality 
of  the  iron  put  into  the  weld. 

In  the  chapter  on  metals  and  their  properties,  we  learned 
that  cast  iron  contained  a  large  amount  of  carbon.  That  this 
carbon  existed  in  the  cast  iron  in  two  conditions,  that  is,  the 
combined  condition  as  white  iron  and  in  the  free  or  graphite 
condition  as  gray  iron.  We  also  learned  that  the  gray  iron  was 
soft  and  that  the  white  iron  was  very  hard,  and  could  not  be 
machined. 

Since  the  majority  of  welds  in  cast  iron  should  be  capable 
of  being  machined,  it  is  indispensable  that  the  weld  should  be 
in  the  condition  of  gray  iron. 


102  OXY-ACETYLENE  WELDING  AND  CUTTING 

When  welding  rods  of  proper  consistency  are  used,  a  good 
soft  gray  iron  weld  can  be  obtained  by  protecting  it  against 
chilling  while  the  melted  metal  is  being  run  in.  This  may  be 
done  by  preheating  and  pursuing  the  methods  prescribed  to  pre- 
vent adhesion. 

Cast  iron  requires  a  flux  to  destroy  the  iron  oxide,  which 
is  less  fusible  than  the  metal  and  which  interposes  itself  in 
the  weld  and  prevents  the  perfect  joining  of  the  molten  metal. 
The  action  of  the  flux  is  to  lower  the  melting  temperature  of 
the  oxide,  which  will  then  float  to  the  surface  where  it  may  be 
removed.  The  flux  is  used  by  putting  the  end  of  the  hot  welding 
rod  into  the  box  of  flux  and  then  working  it  into  the  weld. 

Cast  iron  is  laden  with  impurities  which  form  gases  when 
the  iron  is  melted.  If  the  melted  iron  is  kept  sufficiently  fluid 
these  gases  will  come  to  the  surface  and  disappear,  but  if  the 
metal  is  in  only  a  semi-fluid  state  they  will  remain  in  the  bath 
and  cause  a  spongy  weld.  This  trouble  is  more  noticeable  in 
heavy  work,  which,  if  not  preheated,  will  chill  the  melted  metal 
so  quickly  that  the  gases  cannot  escape. 

The  elimination  of  these  gases  may  be  assisted  by  rotating 
the  torch  around  in  a  little  pool  and  then  gradually  withdraw- 
ing it ;  but  in  so  doing  the  welder  should  be  careful  to  not  blow 
air  and  gases  into  the  melted  metal.  Thoroughly  preheating 
the  casting  will  also  greatly  assist  in  eliminating  the  blow  holes. 

Welding  Malleable  Cast  Iron: — While  the  process  of  auto- 
genous welding  is  being  used  so  successfully  in  all  the  metal 
trades,  many  unsuccessful  attempts  have  been  made  to  weld 
malleable  cast  iron,  and  to  those  who  have  experienced  disap- 
pointment, an  explanation  of  why  their  efforts  failed,  with  an 
outline  of  a  method  by  which  these  castings  can  be  mended, 
should  be  of  benefit. 

Malleable  castings  are  first  made  in  the  condition  of  hard 
brittle,  white  cast  iron  and  subsequently  made  malleable  by 
heat  treatment.  The  heating  process  which  converts  white  cast 
iron  to  malleable  iron  is  called  annealing,  and  effects  a  chemical 
change  in  the  structure  by  decarbonization.  This  decarbonization 
is  nearly  complete  at  the  surface  and  penetrates  in  a  lessening 
degree  toward  the  center,  giving  the  outside  portion  the  texture 


GENERAL  NOTES  ON  WELDING  m:; 

of  mild  steel  while  the  inner  portion  may  retain,  in  a  more  or 
less  degree,  the  qualities  of  cast  iron.  When  this  metal  is  re- 
melted  the  carbon  is  dispersed,  and  the  entire  mass  reverts  to 
cast  iron. 

The  operator  who  is  used  to  welding  mild  steel  and  cast  iron 
will  recall  that  they  are  handled  differently.  That  the  method 
used  in  welding  steel  to  steel  would  be  useless  in  welding  cast 
iron,  or  the  methods  employed  with  cast  iron  would  be  equally 
unsuccessful  with  steel.  That  is  practically  what  he  is  trying 
to  do  when  he  undertakes  to  weld  a  malleable  casting.  The 
material  is  not  homogenous.  The  bottom  portion  of  the  weld 
being  in  cast  iron,  and  the  top  portion  in  steel,  with  no  definite 
dividing  line  between,  it  is  useless  to  follow  the  method  prescribed 
for  either,  and  to  his  trouble  is  added  the  difficulty  occasioned  by 
the  diffusion  of  the  elements  in  the  material  melted  from  the 
sides  of  the  fracture. 

It  follows  that  to  successfully  mend  a  malleable  casting  the 
process  employed  must  not  necessitate  melting  the  sides  of  the 
fracture,  that  the  welding  material  should  fuse  at  a  lower  temper- 
ature than  the  casting,  and  that  its  adherence,  bonding  qualities, 
physical  strength  and  ductility  should  closely  resemble  the  original 
casting.  After  much  study  and  experiment,  the  Vulcan  Process 
Company  and  their  allied  interests  in  Minneapolis  are  having 
considerable  success  in  mending  broken  malleable  castings,  and 
a  description  of  their  methods  will  undoubtedly  be  useful  to 
others  who  are  employed  in  the  metal  trades. 

In  preparing  the  work  for  mending,  the  fracture  is  chipped 
away  in  the  form  of  a  V  groove  with  the  pointed  bottom  just 
coming  to  the  surface  on  the  opposite  side,  or,  if  the  casting 
is  thick  and  the  opposite  side  accessible,  two  grooves  are  cut 
with  their  pointed  bottoms  meeting  in  the  center.  The  part 
surrounding  the  fracture  is  then  heated  with  an  oxy-acetylene 
torch  to  a  bright  red,  and  sprinkled  with  Vulcan  bronze  flux 
followed  by  a  few  drops  of  Tobin  bronze  melted  from  the  weld- 
ing rod.  If  the  bronze  remains  in  a  little  globule  the  work  is 
not  hot  enough,  but  if  it  spreads  and  adheres  to  the  surface,  the 
temperature  is  right,  and  the  groove  should  be  quickly  filled. 
It  is  not  advisable  to  keep  the  work  hot  any  longer  than  is  neces- 


104  OXY-ACETYLENE  WELDING  AND  CUTTING 

sary,  but  to  make  the  mend  as  quickly  and  at  as  low  a  tempera- 
ture as  possible.  The  behavior  of  the  bronze  affords  a  guide 
in  regulating  the  temperature. 

This  process  cannot  be  called  autogenous  welding,  but  a  mal- 
leable casting  mended  in  this  way  is  practically  as  good  as  one 
piece.  It  has  about  the  same  tensile  strength  and  ductility  as  the 
original  and  the  process  has  the  advantage  of  being  very  quickly 
performed. 

Welding  Copper,  Brass  and  Bronze: — Copper  and  all  of  its 
alloys  have  a  faculty  of  absorbing  gases  from  the  flame.  The 
oxide  of  copper  is  very  soluble  in  the  metal  and  forms,  with  it,  an 
alloy  which  crystallizes  in  the  mass  and  destroys  the  homogen- 
eous texture  of  the  weld. 

If  the  autogenous  welding  of  copper  is  obtained  by  melting 
the  edges  and  adding  metal  melted  from  a  pure  copper  welding 
rod,  there  will  necessarily  be  considerable  oxidation  of  the  metal 
and  the  oxide  will  remain  in  the  weld.  The  metal  will  lose  its 
distinctive  properties  and  be  riddled  with  blow  holes.  Xo  ma- 
nipulation or  regulation  of  the  torch  can  overcome  these  defects. 

It  is  therefore  necessary  to  use  a  deoxidizer  capable  of  re- 
ducing the  oxide  as  it  is  formed.  Since  the  oxide  is  dissolved  in 
the  metals  itself,  the  use  of  a  flux  does  not  give  the  expected  re- 
sults. It  is  therefore  necessary  that  the  deoxidizer  be  incorpor- 
ated in  the  welding  rod,  so  that  it  will  be  diffused  continuously 
throughout  the  molten  metal.  All  welds  made  on  red  copper, 
without  the  use  of  deoxidizing  welding  rods,  are  therefore 
strongly  oxidized  and  full  of  blow  holes. 

The  tensile  strength  of  copper  diminishes  rapidly  as  the  tem- 
perature is  raised  and  unless  the  welder  uses  precautions  to  re- 
lieve the  weld  of  strains  while  it  is  hot,  it  will  be  very  likely  to 
crack.  These  strains  may  be  relieved  by  heating  other  parts  of 
the  piece. 

The  weld  should  be  prepared  exactly  the  same  as  for  weld- 
ing iron  or  steel,  and  the  torch  manipulated  the  same  as  described 
before. 

On  account  of  the  conductivity  of  this  metal,  it  might  be  ad- 
visable to  use  a  larger  tip,  on  the  torch,  than  would  be  used  for 
welding  steel.  The  flame  of  the  torch  should  be  perfectly  regu- 


(JENERAL  NOTES  ON  WELDING  105 

lated  and  maintained  without  excess  of  either  gas.  for  if  either 
acetylene  or  oxygen  is  free  in  the  flame  it  will  he  absorbed  in 
the  weld. 

Brasses  and  bronzes  require  the  same  precautions  and  weld- 
ing rods  as  are  used  for  copper;  but  on  account  of  their  con- 
taining other  metals,  it  is  necessary  to  use  a  bronze  flux  in  addi- 
tion to  deoxidizing  welding  rods. 

Welding  Aluminum: — When  aluminum  is  melted  it  oxi- 
dizes very  freely  and  this  oxide  which  clings  to  the  surface  of 
the  metal,  prevents  the  joining  of  the  new  metal  to  the  old.  It 
is  therefore  necessary  to  remove  this  oxide,  which  is  done  by 
scraping  it  out  after  the  metal  is  melted.  Aluminum  melts 
at  a  comparatively  low  temperature  and,  since  the  welder  is 
not  warned  of  the  approaching  melting  temperature,  by  any 
change  in  color,  he  must  use  care  not  to  melt  the  whole  struc- 
ture and  destroy  it.  This  may  occur  in  the  preheating  fire  un- 
less caution  is  used.  Aluminum  like  copper  is  very  weak  when 
hot  and  this  property  combined  with  the  excessive  expansion  of 
the  metal,  is  something  that  may  cause  the  weld  to  break  soon 
after  its  completion  unless  precautions  are  taken  to  remove 
shrinkage  strains,  by  preheating. 

Some  writers  advocate  the  use  of  a  deoxidizing  flux  for 
making  aluminum  welds;  but  others  believe  better  welds  may 
be  obtained  by  the  "puddle"  system  of  welding  than  by  the  use 
of  fluxes.  It  is  the  writer's  observation,  that  excellent  welds  are 
being  made  today  by  the  puddle  system,  and  since  this  method  is 
very  easily  learned,  it  will  be  described  here. 

The  Puddle  System : — Aside  from  the  oxy-acetylene  torch 
and  welding  rods  of  the  purest  aluminum,  the  only  tool  used  is 
a  long  slender  steel  rod,  flattened  on  the  end  to  form  a  paddle 
or  spoon.  This  rod  is  called  a  spatula.  Armed  with  this  tool 
the  welder  will  melt  the  metal  where  the  weld  is  to  be  made 
and  with  the  spatula,  scrape  off  the  surface,  leaving  it  clean  and 
bright.  This  only  removes  the  dirt  for,  although  it  may  not  be 
visible,  oxide  forms  on  the  bright  surface  immediately  behind 
the  spatula,  and  unless  it  is  broken  up  the  new  metal  will  not 
join.  Breaking  up  this  oxide  is  done  after  the  surface  is  covered 


106  OX Y- ACETYLENE  WELDING  AND  CUTTING 

with  new  melted  metal,  which  protects  it  from  further  oxida- 
tion and  is  accomplished  by  gently  scraping  the  spatula  through 
the  mass  of  melted  aluminum  and  removing  it. 

The  operation  is  somewhat  similar  to  scraping  the  skin  off 
melted  babbit;  the  only  difference  being,  that  the  oxide  of 
aluminum  may  be  mixed  with  the  melted  metal.  The  success 
of  the  weld  depends  on  the  thoroughness  of  this  skinning  or 
puddling  operation. 

After  a  little  metal  is  added  and  thoroughly  puddled,  more 
aluminum  is  melted  in  and  the  puddling  repeated. 

The  precautions  to  be  taken  in  welding  aluminum  are  sim- 
ilar to  those  described  before.  It  is  of  primary  importance  to 
never  add  new  metal"  to  a  surface  that  is  not  in  a  molten  condi- 
tion. 

Lead  Burning: — The  process  called  burning  is  used  for  join- 
ing the  edges  of  lead  sheets  or  pipes  without  solder.  The  edges 
are  fused  to  an  extent  which  permits  the  parts  to  unite  and  form 
one  solid  piece  when  cooled.  This  process  is  known  as  the  auto- 
genous process,  and  although  it  has  been  practised  for  centuries, 
it  is  used  far  less  at  the  present  day  than  it  should  be.  It  affords 
a  quick  and  cheap  method  of  making  lead  joints  of  the  most 
durable  character,  and  it  may  be  used  with  profit  in  many 
cases  instead  of  the  soldering  process  now  commonly  employed. 

Solder  cannot  be  used  for  joints  which  are  exposed  to  con- 
tact with  acids,  because  most  of  the  ordinary  acids  will  dissolve 
the  tin,  of  which  the  solder  is  in  part  composed. 

Tanks  which  are  used  for  the  manufacture  or  storage  of 
acids  or  acid  salts,  or  for  the  storage  of  mineral  oils,  petroleum, 
etc.,  are  usually  lined  with  lead.  The  joints  in  these  linings, 
and  in  all  of  the  lead  pipes  which  are  used  for  the  same  purpose, 
must  be  made  by  burning. 

The  operation  is  performed  by  melting  the  edges  to  be  joined 
a  drop  at  a  time,  by  means  of  a  torch.  It  is  essential  that  the 
flame  which  is  used  shall  not  oxidize  or  tarnish  the  metal.  If 
the  •  drop  of  melted  metal  does  oxidize,  it  will  not  unite  with 
the  solid  parts,  and  the  joint  will  be  a  failure. 


GENERAL  NOTES  ON  WELDING  107 

The  most  certain  and  convenient  way  to  secure  a  non-oxidiz- 
ing flame  is  to  use  hydrogen  gas  mixed  with  air  to  supply  the 
torch.  Other  methods  may  be  employed,  but  none  are  so  con- 
venient as  the  hydrogen  gas  process. 

A  FEW  EXAMPLES  IN  WELDING. 

In  describing  a  few  examples  on  welding,  we  will  consider 
that  the  welder  has  acquired  a  knowledge  in  handling  his  torch 
and  welding  the  various  kind  of  materials,  so  this  detail  will  be 
omitted,  and  the  illustration  confined  to  a  description  of  the  prep- 
aration incidental  to  the  particular  example. 

Welding  a  Crank  Shaft : — The  difficulties  is  welding  a  crank 
shaft  as  shown  in  Figure  45,  are  not  in  the  performance  of  weld- 
ing; but  in  providing  for  expansion  and  securing  alignment, 
that  will  obviate  the  necessity  of  much  machine  work. 


Fig.  45 
CRANK  SHAFT  ON  V  BLOCKS  PREPARED  FOR  WELDING 

Before  assembling  for  welding  the  fracture  is  ground  away 
to  form  a  V  groove,  as  is  usual  in  preparing  any  weld,  but  in 
this  case  there  is  about  an  eight  of  an  inch  of  the  fracture  left 
undisturbed.  This  is  to  furnish  a  guide  for  adjusting  the  pieces. 
The  shaft  is  then  clamped  in  V  blocks  like  those  shown  in  the 
picture.  These  V  blocks  have  a  piece  of  cardboard  or  sheet 


ION 


OXY- ACETYLENE  WELDING  AND  CUTTING 


iron  placed  between  the  sloping  side  of  the  block  and  the  long  V 
bar  which  holds  them.  In  the  picture  above  these  pieces  of 
sheet  iron  would  be  on  the  far  side  of  the  two  blocks  shown  to 
the  left  and  on  the  near  side  of  the  block  shown  to  the  right 
and  when  the  crank  shaft  is  clamped  in  position,  they  would 
cause  an  opening  to  show  between  the  fractured  ends  of  the 
crank  shaft.  This  opening  is  to  take  care  of  expansion  and 
should  be  about  1-32  of  an  inch.  With  the  torch,  the  part  sur- 
rounding the  weld  will  be  heated  until  this  space  is  closed  up  by 
expansion,  and  then  the  V  shaped  opening  welded  full.  Before 
shrinkage  takes  place  the  clamps  and  strips  of  sheet  metal  are 
removed,  when  this  part  of  the  weld  become  rigid,  the  unwelded 
portion  on  the  back  is  melted  out  and  welded  full. 

Welding  the  Inner  Wall  of  an  Auto  Cylinder: — A  portion  of 
the  water  jacket,  outside  the  fracture,  is  cut  out  by  drilling  as 
shown  in  Figure  46. 


Fig.  46 
AUTO  CYLINDER  PREPARED  FOR  WELDING 

The  whole  cylinder  is  then  put  into  a  preheating  fire  with  the 
fractured  side  up  and  when  sufficiently  heated  the  covering  is 
laved  aside  and  the  fracture  melted  away  with  the  torch  and 


GENERAL  NOTES  ON  WELDING  ]o<> 

welded  full.  The  piece  which  was  cut  out  of  the  water  jacket 
is  then  welded  back  into  place.  For  convenience  in  holding  this 
piece  in  place  while  it  is  being  fastened,  a  small  rod  may  be 
welded  in  the  center,  to  form  a  handle. 


WELDING  AUTO  SPRINGS. 

The  usual  method  in  welding  auto  springs,  is  to  first  bring 
the  spring  to  its  normal  position  and  block  it  up  with  bricks 
to  hold  it  in  alignment  while  it  is  being  welded.  Then  with  the 
oxy-acetylene  torch  the  fracture  is  quickly  melted  and  run  to- 
gether. 

The  process  differs  from  welding  mild  steel  in  the  fact  that 
the  edges  of  mild  steel  plates  are  separated  a  short  distance  to 
facilitate  the  flame  entering  between  them,  the  space  being  filled 
with  material  melted  from  the  welding  rod ;  but  when  welding 
springs,  the  edges  are  brought  tight  together  and  a  narrow  strip 
of  the  material  adjoining  the  fracture  is  melted  from  the  top 
down  through  to  the  bottom,  adding  only  as  much  material 
from  the  welding  rod  as  is  required  to  restore  the  normal  thick- 
ness. When  this  has  been  done  on  one  side  it  is  repeated  on  the 
other;  but  this  time  it  is  not  necessary  to  weld  as  deep. 

The  portion  of  the  spring,  which  has  just  been  welded,  is  a 
little  softer  than  the  rest  and  is  not  as  liable  to  break  from  shock. 
It  is  not  the  custom  to  retemper  this  part  of  the  spring  for  very 
good  results  are  obtained  without.  To  make  this  part  of  the 
same  temper  as  the  rest,  would  require  retempering  the  whole 
spring,  which  is  an  undertaking  not  to  be  recommended  to  any 
one  who  is  not  skilled  in  that  line  and  provided  with  a  suitable 
heating  furnace  and  oil  bath.  Even  then  it  is  a  treacherous  job 
and  better  results  are  usually  obtained  by  leaving  the  weld  tin* 
tempered. 

It  is  well  for  the  reader  to  refer  to  the  illustrations  on  page 
i,  2,  and  7  and  note  the  temporary  grates  which  were  con- 
structed to  sustain  the  preheating  fire. 


110  OXY-ACETYLENE  WELDING  AND  CUTTING 

CHAPTER  XII. 

CUTTING  IRON  AND  STEEL  WITH  THE  OXYGEN  JET. 

The  rapid  combustion  of  iron  in  oxygen  has  been  known 
for  over  a  century  and  was  mentioned  by  Lavoisier.  The  chem- 
ical treatise  on  this  subject  mention  that  iron  oxide  formed  is 
more  fusible  than  the  iron  and  is  detached  as  the  combustion 
proceeds,  continually  exposing  the  bare  iron  to  the  attack  of 
the  oxygen. 

It  is  this  phenomenon  that  makes  possible  the  rapid  cutting 
of  iron  and  steel,  with  a  torch  and  oxygen  jet,  and  although  it 
has  been  known  so  long  it  was  not  until  recent  years  that  the 
process  was  used  industrially.  ' 

All  thicknesses  can  be  cut  from  the  thinnest  sheets  to  heavy 
armor  plates  for  battle  ships.  The  process  is  also  being  used 
extensively  in  steel  foundries  for  cutting  the  gates  and  risers  from 
steel  castings.  In  fact  the  uses  to  which  it  may  be  advantage- 
ously applied  are  innumerable,  and  as  people  become  better 
acquainted  with  it,  they  are  finding  new  uses  for  it.  On  pages 
5  and  6  are  mentioned  a  few  of  the  recent  applications  of  this 
process,  to  cutting  the  wreckage  of  ore-docks  and  sunken  ships. 

The  Theory : — All  instructions  in  autogenous  welding  cau- 
tion the  operator  to  use  a  perfectly  neutral  flame,  for  if  he  uses 
too  much  oxygen,  he  is  told,  the  metal  will  become  oxidized,  or 
burned  up.  If  a  small  piece  of  iron,  or  steel  is  heated  and  drop- 
ped into  oxygen  it  will  burn  rapidly.  The  iron  actually  be- 
comes a  fuel  and  is  burned  in  the  oxygen ;  and  in  burning  it 
generates  heat  just  the  same  as  any  other  fuel  would  do  in 
burning.  This  phenomenon  which  is  so  carefully  avoided  when 
making  welds,  is  used  to  advantage  in  oxy-acetylene  cutting. 
The  torch  is  arranged  to  first  deliver  a  hot  neutral  oxy-acetylene 
flame  until  the  metal  is  at  a  white  heat,  then  a  jet  of  oxygen  is 
impinged  against  this  hot  metal  and  iron  burning  or  oxidation 
ensues. 

The  oxidation  commences  at  the  part  which  has  previously 
been  heated  to  redness,  because  at  this  temperature  the  reaction 
takes  place  more  radiply.  The  combustion  or  burning  of  this 


CUTTING  IRON  AND  STEEL  WITH  THE  OXYGEN  JET       111 

portion  of  the  iron,  liberates  heat,  a  portion  of  which  is  absorbed 
by  the  surrounding  iron,  and  raises  it  to  a  red  heat,  so  that  in 
turn  it  burns.  This  burning  is  progressively  extended  by  moving 
the  torch  along  the  line  of  the  cut. 

This  burned  iron  is  known  to  chemists  as  oxide  of  iron  and 
when  first  formed  it  may  appear  as  a  solid  scale  adhering  to 
the  surface  of  the  iron.  If  it  remain  there  it  protects  the  iron 
against  any  further  oxidation  or  burning  just  the  same  as  a  thick 
covering  of  ashes  will  stop  the  burning  of  wood.  Wrought  iron 
and  mild  steel,  melts  at  a  much  higher  temperature  than  does 
the  oxide  of  iron.  So  on  these  substances  the  oxide  will  melt 
first  and  run  off  leaving  the  surface  of  the  metal  clean,  and  con- 
tinually exposed  to  the  attacks  of  the  oxygen  jet. 

The  oxide  on  cast  iron  cannot  be  melted  off  to  expose  the 
clean  surface  to  the  attack  of  the  oxygen  jet,  because  its  melting 
temperature  is  higher  than  that  of  the  metal.  It  may  be  melted, 
but  the  metal  melts  first  and  the  oxide  mixes  with  it.  The  proc- 
ess is  not  the  clean  rapid  cutting  action  obtained  with  mild 
steel,  or  wrought  iron,  but  is  merely  one  of  melting.  It  is  there- 
fore said  that  cast  iron  cannot  be  cut  by  the  oxy-acetylene  proc- 
ess. This  is  also  true  of  copper,  brass,  bronzes,  aluminum,  and 
very  high  carbon  steel. 

Using  the  Torch: — In  using  the  oxy-acetylene  cutting  torch 
it  is  advisable  to  first  adjust  the  regulator  on  the  oxygen  drum 
to  deliver  oxygen  at  10  to  50  pounds  pressure,  according  to  thick- 
ness of  the  metal.  Then  turn  on  a  little  acetylene,  ignite  it,  and 
open  the  needle  valve  in  the  handle  of  the  torch  until  the  base 
of  the  flame  appears  to  leave  the  torch  and  stands  away  about 
an  eighth  of  an  inch.  The  acetylene  flame  is  now  a  large,  flar- 
ing, smoky,  irregular  shaped  mass,  but  open  the  little  needle 
valve  that  controls  the  oxygen  supply  and  the  flame  will  com- 
mence to  assume  definite  size  and  proportion.  Continue  to  slowly 
open  this  valve  and  there  will  appear  an  inner  white  flame  that 
blends  with  a  thin  feathery  edge  into  a  pale  blue  outer  flame, 
and  as  the  oxygen  supply  is  slowly  increased  this  inner  white 
flame  becomes  smaller,  and  the  outline  more  distinct.  When 
the  thin  feathery  outline  of  this  inner  flame  is  entirely  gone  and 


112  OXY-ACETYLENE  WELDING  AND  CUTTING 

the  dividing  line  between  the  two  parts  of  the  flame  is  distinct. 
the  oxygen  supply  is  sufficient,  and  the  flame  is  neutral. 

To  start  the  cutting  action,  the  little  white  inner  flame  should 
be  held  about  three  sixteenths  of  an  inch  from  the  metal  until  it 
begins  to  melt,  then  the  thumb  lever  is  pressed  which  starts  a  flow 
of  oxygen  through  the  cutting  tip.  When  the  oxygen  comes  in 
contact  with  the  metal  it  burns  it  very  rapidly,  and  oxide  of  iron 
runs  or  is  blown  out  of  the  cut.  When  starting  a  cut  in  the  middle 
of  a  plate  of  steel,  there  is  no  place  for  this  melted  iron  oxide 
to  run  out,  so  it  gathers  in  a  little  puddle  where  the  force  of  the 
torch  blows  and  spatters  it.  In  this  event  care  should  be  taken  to 
prevent  it  splashing  into  the  end  of  the  torch.  This  may  be  pre- 
vented by  holding  the  torch  a  little  farther  away  from  the  plate 
than  would  be  necessary  in  starting  the  cut  at  the  edge. 

After  the  cut  is  started  and  there  is  a  place  for  the  iron  oxide 
to  escape,  the  torch  may  be  brought  a  little  closer  to  the  work  and 
steadily  advanced  without  wabbling  or  tilting,  moving  evenly 
along  the  line  of  cut  as  fast  as  the  metal  will  burn  and  run  out. 
If  the  torch  is  held  too  far  away,  the  action  is  slower  and  the  gap 
of  the  cut  is  wider,  while  if  it  is  too  close,  particles  of  burned  iron 
may  enter  the  torch.  A  jerky,  wabbly  movement  makes  a  ragged 
cut.  Plates,  y%  or  3-16  inches  thick,  can  be  cut  with  the  ordinary 
welding  torch,  by  first  heating  the  metal  to  a  white  heat  with  the 
oxy-acetylene  flame  and  then  shutting  the  acetylene  entirely  off 
and  using  the  oxygen  jet  the  same  as  in  the  regular  cutting  torch. 
The  heat  of  the  burning  steel  is  sufficient  to  cause  the  combus- 
tion of  the  adjoining  material  and  thus  the  operation  is  contin- 
uous without  the  use  of  the  preheating  flame  which  accompanies 
the  cutting  torch. 

The  jerky  wabbly  movement,  previously  mentioned,  not  only 
makes  a  ragged  cut,  but  it  retards  the  progress  of  the  cut  and 
adds  to  the  cost  of  the  operation.  In  consequence  of  this,  there 
have  been  cutting  machines  designed,  which  carry  the  torch  at 
any  desired  angle  and  at  a  uniform  speed  across  the  work.  To 
obtain  the  best  results  some  arrangement  of  this  kind  is  required. 

In  figure  No.  47  is  shown  a  machine  of  the  kind  just  described, 
which  is  designed  to  cut  bars  or  structural  shapes.  The  piece 
to  be  cut  is  clamped  in  the  V  shaped  notch,  and  the  cutting  torch. 


CUTTING  IKON  AND  STEEL  WITH  THE  OXYGKN  .1  KT       113 

which  is  easily  discernable  in   the  picture,    is  carried    steadily 
across  the  work  by  means  of  a  screw. 

A  simple  device  for  cutting  elliptical  man  holes  in  boiler 
plates,  may  be  made  by  providing  a  track,  of  angle  iron,  formed 
to  the  shape  of  the  desired  manhole  and  equipped  with  a  carriage 
to  carry  the  torch.  The  carriage  can  be  of  the  easiest  construc- 
tion, and  provided  with  three  wheels,  two  of  which  will  ride  on 
the  track  and  one  on  the  plate. . 


Fig.  47 
MACHINE  FOR  CUTTING  BARS  AND  STRUCTURAL  SHAPES 

The  machine  shown  in  the  following  figure  No.  48  is  designed 
for  cutting  circular  plates  or  holes.  The  heavy  base  which  serves 
as  a  center,  is  held  in  place  by  its  weight,  and  affording  a  bear- 
ing for  the  upright  stud  which  carries  the  horizontal  bar.  The 
bar  slides  through  the  stud  and  may  be  clamped  in  any  position 
that  will  give  the  required  diameter  to  the  circle.  After  this  ad- 


114 


OXY-ACETYLENE  WELDING  AND  CUTTING 


justment  has  been  made,  the  stud  is  rotated  in  the  base,  by  hand, 
carrying1  the  torch  around  in  the  path  of  a  circle.  The  torch 
shown  in  these  two  illustrations  is  especially  designed  for  ma- 
chine use. 


Fig.  48 
MACHINE  FOR  CUTTING  CIRCULAR  PLATES  AND  OPENINGS 

Structural  iron  workers,  erecting  contractors,  and  others  en- 
gaged in  building  or  tearing  down  old  structures,  find  the  oxygen 
cutting  process  of  great  service  to  them.  The  saving  which  re- 
sults from  its  use  may  be  judged  by  the  reader,  after  noting  the 
table  of  cutting  speeds  and  costs  as  noted  below. 


Thickness 
of 
plate 

Cost  of  gas  @  2c  per  foot 

Time  per 
foot 
in  seconds 

Oxygen 

Acetylene 

y2 

$0.0082 
0.0154 
0.0244 
0.0306 

$0.0026 
0.0034 
0.0042 
0.0066 

30 
38 
46 

(TTTIMJ   IRON    AND  STKKL  WITH  TIIK  OXYGEN   .1  KT        1  ir, 


Fig.  49 
CUTTING  OLD  STKKL  FLOOR    BKAMS 


During-  the  year  1914  the  old  union  depot  in  Minneapolis  was 
torn  down  to  make  room  for  a  new  building". 

All  the  structural  steel  members  in  this  building-  were  removed 
by  cutting  them  free,  with  the  oxy-acetylene  cutting  torch.  The 
above  picture  was  made  from  a  photo,  of  the  cutters,  while  at 
work.  The  process  was  eminently  successful  and  showed  a  great 
saving  over  the  old  method  of  removing  them  by  knocking  off  the 
rivet  heads,  or  sawing. 


116  OXY- ACETYLENE  WELDING  AND  CUTTING 


REDUCING  AN  OLD  BOILER  TO  SCRAP 


It  was  recently  required  to  remove  an  old  steam  boiler  from 
the  sub-basement  of  a  department  store.  The  boiler  had  been 
in  use  many  years,  during  which  time  the  building  had  been  re- 
modeled and  brick  walls  built,  in  a  way  that  required  their  de- 
struction to  remove  the  boiler  in  one  piece.  With  the  oxy-acety- 
lehe  cutting  torch  the  boiler  was  quickly  reduced  to  scrap  and  re- 
moved in  pieces. 


CUTTING  IRON  AND  STKEL  WITH  THE  OXYGEN  .1  KT       117 


Fig.  51 
REDUCING  AN  OLD  BOILER  TO  SCRAP 


118  OXY-ACKTYLKXK   WELDING  AND  CUTTING 

CHAPTER  XIII. 

BOILER  MAKING  AND  SHEET  METAL  WORK. 

There  is  perhaps  no  class  of  work  where  the  oxy-acetylene 
cutting-  and  welding  processes  can  be  used  to  better  or  as  good 
advantage  as  in  boiler  and  sheet  metal  work. 

Boiler  makers  who  consented  to  give  the  process  a  trial  in 
their  shops,  were  surprised  and  marveled  at  the  savings  they 
could  realize  by  its  continual  use.  Even  then  they  had  not  learned 
of  all  the  applications,  of  which  this  apparatus  was  capable,  and 
every  day  they  are  finding  new  places  where  the  process  can 
save  them  time  and  money. 

A  Superintendent,  of  Motive  Power,  on  one  of  our  promi- 
nent railroads,  recently  made  the  statement  that  the  oxy-acetylene 
plant  in  his  shops,  was  saving  for  his  company,  an  average  of 
lour  dollars  an  hour,  for  every  hour  a  torch  is  in  use.  The 
torch  has  such  universal  application,  and  the  operations  to  which 
it  can  be  advantageously  applied,  are  so  general  and  frequent, 
they  can  hardly  be  enumerated  ;  but  as  the  welder  becomes  familiar 
with  the  process  he  finds  them  himself. 

To  sustain  these  statements,  we  will  cite  a  few  instances 
where  the  operation  proved  its  superiority  over  old  methods. 

Cutting  a  full  door  patch  for  a  locomotive  boiler,  usually  re- 
quired 6  hours  time  for  a  boiler  maker,  and  his  helper,  at  an 
average  total  cost  of  $4.04.  The  same  job  done  by  the  oxy- 
acetylene  process,  required  nine  minutes  time  and  cost  25  cents 
for  labor  and  gas. 

Cutting  a  side  sheet  and  door  sheet  by  the  old  method,  re- 
quired 1 8  hours  time  of  two  men  and  usually  cost  $12.15.  By 
the  new  method,  the  same  work  was  done  in  thirty  minutes  at 
a  cost  of  83  cents. 

Another  incident  is  in  welding  an  outside  sheet.  On  previous 
occasions  it  required  the  work  of  two  men  for  16  hours  and 
cost  $10.80  to  make  the  repair,  which  was  welded  with  an  oxy- 
acetylene  torch  in  3  hours  time  at  a  total  cost  of  $5.85. 

'A  cracked  sheet,  usually  required  patching  and  to  do  this 
at  an  average  cost  of  $15.00  was  good  work;  but  with  the  oxy- 


BOILKH    MAKING    AND  SI  I  KMT   MKTAL   WOKK  11!) 

acetylene  process,  the  crack  can  be  welded  and  the  sheet  made 
as  good  as  new,  at  a  cost  of  $4.00.  The  welded  crack  has  an 
advantage  over  the  patch,  in  the  fact  that  it  only  presents  din- 
thickness  of  metal,  to  the  action  of  the  fire.  This  advantage  i- 
well  appreciated  by  boiler  makers. 

To  reduce  an  old  boiler  to  commercial  scrap,  required  the 
labor  of  two  men  for  80  hours  and  usually  cost  about  $40.00. 
The  same  work  can  be  done  with  one  man  using  the  oxy-acetylene 
torch  in  yl/2  hours  and  will  cost,  for  labor  and  gas,  about  $12.00. 

The  question  will  probably  occur  to  some  practical  boiler 
makers,  whether  an  oxy-acetylene  welded  seam  will  withstand 
the  action  of  fire.  In  answer  to  this  we  will  cite  an  incident. 
in  Duluth,  where  it  was  desired  to  construct  a  bosh  jacket,  for 
one  of  the  large  blast  furnaces  being  built  there  at  that  time. 
It  was  particularly  desired  to  get  a  smooth  seam,  so  that  the 
cooling  water  would  stay  on  the  jacket,  better  than  was  possible 
for  a  film  of  water  to  do  on  such  a  surface  when  broken  by 
seams  and  rivets,  and  also  to  have  only  one  thickness  of  metal, 
to  eliminate  the  great  liability  of  burning,  due  to  double  thick- 
ness. 

The  bosh  jacket  was  in  the  form  .of  a  truncated  cone,  and 
was  eleven  feet  in  diameter  at  the  bottom,  sixteen  feet  at  the 
top,  nine  feet  high,  and  made  of  half  inch  stock  throughout. 

In  fabricating  this  job  it  was  built  in  four  sections  or  seg- 
ments and  welded  along  the  vertical  joints,  with  an  oxy-acetylene 
torch.  When  the  welds  were  finished  the  joints  were  ground 
smooth  and  were  hardly  perceptible.  The  job  was  eminently 
satisfactory  and  in  several  years  of  continuous  service,  has  shown 
no  indication  of  weakening  at  the  welded  joints. 

Welding  Pieces  of  Different  Thickness: — Oxy-acetylene  weld- 
ing is  not  easily  applied  to  pieces  of  different  thickness,  because 
the  melting  of  the  two  edges  is  not  equal,  and  does  not  take 
place  at  the  same  time.  Since  the  torch  is  too  powerful  for  the 
thin  piece  or  too  weak  for  the  thick  piece.  A  clever  welder, 
however,  can  manage  his  torch  so  that  the  heat  given  to  the 
two  edges  is  proportional  to  their  thickness;  but  if  the  differ- 
ence is  very  great,  the  joint  is  not  easily  obtained. 


120 


OXY-ACETYLENE  WELDING  AND  CUTTING 


Effects  of  Expansion: — The  effects  of  expansion  often  act 
in  such  manner  that  the  edges  to  be  poined  separate  and  approach 
each  other  alternately.  If  one  wishes  to  join  two  plates  by  auto- 
genous welding,  and  the  edges  have  been  arranged  parallel,  when 
the  weld  has  commenced  one  first  observes  a  widening  of  the 
space,  at  the  other  end  of  the  plate.  See  figure  53.  If  the  weld- 
ing is  continued,  the  deviation  quickly  stops  and  the  opposite 
movement  takes  place,  that  is,  the  edges  approach,  and  as  the 
weld  advances  they  will  overlap  each  other.  See  figure  54. 


Fig.  66. 
FABKICATING  A  BOSH  JACKET  IN  SHOPS  AT  DULUTH,  MINN. 


BOILER  MAKING  AND  SHEET  METAL  WORK 


Fig.  52  Fig.  53  Fig.  54 

EXAMPLES  OF  EXPANSION 

To  overcome  this  final  overlaping,  two  methods  may  be  fol- 
lowed: one  is  to  separate  the  edges  before  commencing  to  weld, 
as  shown  in  figure  55,  and  the  other  to  weld  in  spots  about  a 
foot  apart,  throughout  the  length  of  the  joint.  This  latter 
method  is  called  tacking. 

In  the  first  case  the  initial  separation  should  be  about  1-20 
of  the  length  of  the  weld,  and  as  the  weld  progresses  the  space 
at  the  far  end  may  be  allowed  to  close  a  small  amount,  thus  con- 
tinue closing  the  space  as  the  weld  advances,  at  a  ratio  that  will 
bring  the  edges  together  when  the  weld  reaches  the  end.  In 
starting  this  job  the  edges  will  first  be  placed  parallel  until  a 
few  inches  are  welded  and  then  they  will  be  sprung  open,  as  sug- 
gested. 


Fig.  55 

METHOD  OF  OVERCOMING  EFFECTS  OF  EXPANSION,  WHILE 
WELDING  PARALLEL  EDGES 


]2L>  OXY- ACETYLENE   WELDING  AND  CUTTING 

If  the  system  of  tacking  is  used,  the  expansion  cannot  act 
laterally,  as  in  the  previous  case,  and  this  causes  a  deformation 
as  shown  in  figure  56.  In  the  majority  of  cases,  it  is  easy  to 
bring  the  plates  back  to  the  original  position. 


Fig.  .16 

DEFORMATION  CAUSED  BY  EXPANSION  WHEN  THE  .JOINT  HAS 
BEEN  PREVIOUSLY  TACKED 

The  Preparation  of  Joints: — Welding  very  thin  pieces,  is 
especially  difficult  on  account  of  the  great  liability  of  melting 
holes  through  the  material.  In  this  kind  of  work,  the  method 
of  overlapping  the  edges  as  shown  in  figure  57  is  very  faulty.  The 
best  method  being  to  bend  the  edges  up  as  shown  in  figure  58. 
These  upturned  edges  are  melted  down  and  furnish  welding 
material. 

If  the  plates  are  thick  enough  to  permit  beveling  they  may 
be  prepared  as  in  figures  59  and  60.  This  is  explained  quite 
thoroughly  under  "General  Notes  on  Welding!" 

In  Joining  plates  at  right  angles,  the  groove  for  Welding  is 
obtained  without  beveling,  by  simply  arranging  as  shown  in 
figure  62. 

The  joint  in  figure  61,  which  is  not  beveled  at  all,  is  bad 
when  the  plates  are  over  l/§  of  an  inch  thick,  because  the  amount 
of  penetration  is  doubtful.  The  arrangement  shown  in  figure 
63  is  favorable  from  the  view  point  of  penetration,  but  the  weld 
is  difficult  to  make  and  in  figure  64  the  difference  in  thickness 
between  the  beveled  side  and  the  unbeveled  side,  makes  the  job 
difficult  for  the  reason  that  the  heavy  part  requires  more  heat 
than  the  other ;  but  the  joint  can  be  successfully  made  by  skillful 
manipulation. 


BOILKR  MAKINc    AND  slIKKT   MKTAL  WORK 


Pig.  -I; 


Fig.  58 


Fig.  59 


Fig.  60 


Fig.  62 


Fig.  <>:;  Fig.  (H 

GOOD  AND  BAD  EXAMPLES  OF  1'KKI'AKKD  .JOINTS 


124  OXY-ACETYLENE  WELDING  AND  CUTTING 

Welding  a  Crack  in  a  Boiler  Sheet : — It  is  very  exasperating 
and  sometimes  embarrassing  to  the  welder,  to  nicely  finish  a 
weld  in  a  cracked  plate,  and  then  stand  back  and  see  it  reopen 
and  grow  a  few  inches  longer,  when  the  sheet  cools  off.  This 
is  sure  to  happen  unless  some  provision  is  made  to  take  care 
of  the  expansion. 

A  careful  study  of  this  phenomenon  will  be  of  benefit,  and 
when  the  principle  is  understood  it  will  help  to  solve  other  dif- 
ficulties which  will  occur  in  boiler  work. 

When  the  metal  around  the  crack  is  brought  to  a  welding 
heat,  it  becomes  soft  and  incapable  of  resisting  compression, 
consequently,  the  expansion  caused  by  the  heat,  pushes  the  soft 
metal  together,  so  that  when  it  cools  off  it  would  be  shorter  than 
it  was  before;  but  to  shorten  is  impossible,  because  it  is  a  part 
of  a  cold,  solid,  uncompromising  plate.  The  tension  thus  caused 
by  the  shrinkage  is  enormous. 

If  the  weld  was  strong  enough  to  hold,  it  would  produce 
strains  in  the  rest  of  the  boiler  and  would  be  objectionable. 

To  successfully  weld  a  crack  of  this  kind,  it  is  only  necessary 
to  relieve  the  sheet  of  the  strains  resulting  from  shrinkage,  and 
this  may  be  done  by  preheating  an  extensive  portion  of  the  plate, 
at  each  end  of  the  fracture,  and  keep  it  hot  during  the  whole 
performance  of  welding. 

Preheating  in  this  way  will  cause  the  fracture  to  open  and 
when  the  welder  can  clearly  see  the  opening,  he  can  apply  his 
process  to  the  weld  and  finish  as  in  welding  any  other  plate. 
Then  when  the  whole  area  cools  it  will  resume  its  normal  posi- 
tion and  be  void  of  strains  or  the  liability  to  crack. 

After  reading  the  preceding  pages  of  this  book,  the  welder 
should  not  need  cautioning,  to  be  sure  and  weld  deep  through  to 
the  other  side  of  the  plate. 

Welding  in  a  Patch : — In  welding  in  a  patch,  the  effects  of 
expansion  and  contraction  can  be  overcome  without  preheating. 
This  is  done  by  "dishing"  the  patch. 

Cut  the  patch  a  little  bigger  than  the  hole  and  then  "dish" 
it  until  the  outside  edges  just  fill  the  opening.  After  bevel- 
ing the  edges  of  the  hole  and  patch,  it  is  inserted  in  the 
opening  with  the  convex  side  out,  and  tacked  in  several  places  to 


BO1LKR   MAKING  AND  SHP^KT  METAL  WORK  li>r, 

secure  it.  Finish  the  weld  as  instructed  in  previous  paragraphs 
and  when  shrinkage  ensues,  the  convex  patch  is  flattened  down 
with  a  hammer.  Flattening  the  patch  enlarges  it  and  compensates 
for  the  shrinkage. 

Welding  Flues: — The  oxy-acetylene  torch  can  be  used  very 
successful  for  re-tippirg  flues.  By  the  old  method  flues  and  tips 
were  scarfed,  brought  to  a  welding  heat  in  the  blacksmith  forge 
and  then  welded  by  means  of  hammer  blows.  To  do  this  work 
properly  it  would  therefore  require  the  services  of  an  experienced 
blacksmith  and  in  comparison  to  the  new  method  takes  consi- 
derable longer.  Flues  can  best  be  re-tipped  by  means  of  the 
oxy-acetylene  torch  by  first  grinding  the  ends  of  the  flue  and 
tip  to  a  bevel  edge,  butting  the  beveled  ends  together  and  weld- 
ing them  in  place.  Care  must  be  taken  not  to  allow  the  metal  to 
flow  through  and  leave  a  rough  edge  on  the  inside.  Should  this 
occur,  the  end  of  the  flue  could  be  slipped  over  a  piece  of  round 
shafting  to  be  used  as  a  mandrel,  and  hammered  smooth.  Very 
little  extra  metal  should  be  added  on  the  outside  otherwise  the 
flue  would  not  pass  through  the  flue  sheet. 

Where  a  comparatively  pure  supply  of  water  is  available,  it 
has  been  found  practicable  to  weld  the  flues  directly  to  the  flue 
sheets.  When  they  are  so  welded,  it  is  of  course  difficult  to  take 
them  out  and  hence  this  method  is  not  recommended  where  it 
is  necessary  to  frequently  remove  the  flues. 

In  welding  new  flues  to  the  flue  sheet,  they  should  be  welded 
on  one  end  only,  the  other  end  being  rolled.  The  welding  should 
be  done  first  leaving  the  other  end  free  to  take  care  of  the  ex- 
pansion and  contraction.  The  flue  should  be  allowed  to  extend 
through  the  flue  sheet  about  one-eighth  inch  or  three-sixteenths 
inch  and  then  welded  around  between  the  end  of  the  flue  and 
the  sheet. 


Ji'ii  OXY- ACETYLENE  WELDING  AND  CUTTING 

CHAPTER  XIV. 

CARBON  BURNING. 

Carbon  is  a  fuel.  It  is  the  carbon  in  coal  that  burns  and  gives 
us  heat  by  chemically  uniting"  with  oxygen  to  form  carbon 
dioxide  as  explained  on  page  17.  Soot  is  carbon  which  has 
been  liberated  by  heat,  and  for  lack  of  oxygen  was  not  consumed. 
If  soot  can  be  heated  in  the  presence  of  oxygen  it  will  burn  and 
leave  no  ashes,  but  if  the  oxygen  is  derived  from  the  air  this  is 
difficult  to  accomplish  because  the  predominance  of  nitrogen,  in 
the  air,  absorbs  the  heat  of  reaction,  lowering  the  temperature 
below  the  point  at  which  the  carbon  will  burn.  When  pure 
oxygen  is  used,  the  burden  of  nitrogen  is  avoided  and  the  carbon 
will  burn  rapidly. 

Soot  or  carbon  frequently  accumulates  in  the  compression 
chamber  of  internal  combustion  engines,  to  such  an  extent  that 
it  interferes  with  its  perfect  working. 

In  the  past,  it  has  been  the  practice  of  mechanics  to  remove 
this  carbon  by  scraping".  The  operation  required  considerable 
time  and  was  quite  an  expense ;  but  since  the  advent  of  cheap 
oxygen,  this  carbon  is  being  removed  by  burning'  it. 

The  process  consists  of  starting  combustion  with  a  little 
kerosene,  which  is  sprinkled  into  the  cylinder,  ignited  and  im- 
mediately followed  with  a  stream  of  oxygen.  The  carbon  flashes 
into  a  flame  and  as  long  as  it  is  fed  with  oxygen  it  burns  to  the 
last  trace. 

By  this  method  a  four  cylinder  motor  can  be  cleaned  in  twenty 
minutes,  at  a  very  trifling  expense. 

Directions  for  a  Carbon  Burner: — Have  the  piston  at  the  top 
of  the  compression  stroke,  and  remove  the  spark  plug  and  valve 
cap.  Then  sprinkle  about  half  a  tablespoon  of  kerosene  into  the 
valve  chamber,  and  cylinder  head.  After  is  has  soaked  into  the 
carbon,  light  it  and  immediately  insert  the  long  slender  nozzle 
of  the  torch.  When  the  oxygen  comes  in  contact  with  the  car- 
bon it  will  burst  into  flames  and  during  the  earlier  part  of  the 
process,  these  flames  will  rush  from  all  the  openings.  For  this 
reason  it  is  advisable  to  keep  the  face  away  from  the  work. 


CARBON     BfRNINCi  1^7 

\\'hen  the  carbon  diminishes  the  flame  will  be  replaced  by 
sparks  and  the  flow  of  gas  should  be  increased,  to  make  it  hunt 
all  the  little  corners.  This  may  be  assisted  by  thrusting  the  torch 
around  into  different  parts. 

If  the  flame  goes  out  suddenly,  put  in  more  kerosene  and  re- 
light it.  This  may  have  to  be  repeated  several  times.  After  the 
cylinder  is  cleaned,  blow  all  the  loose  particles  out  with  com- 
pressed air. 

Cleaning  cylinders  in  this  way  does  not  heat  them  to  as  high 
a  temperature  as  they  attain  in  service. 


CARBON  Bt'KNKK   AT   \\OKK 


OXY-ACETYLEXE  WELDING  AND  CUTTING 


§!§i 

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USEFUL  INFORMATION 


129 


TABLE  XII 
QUANTITY    OF   GAS   IN    CYLINDERS 

Under   Varying  Pressures   and   Constant   Temperatures 
Rated  capacity  and  pressure  of  drum,  at  68°  Fahrenheit 


100  Cubic  Feet  at 

100  Cubic  Feet  at 

200  Cubic  Feet  at 

300  Lhs   Pressure. 

1800  Lbs   Pressure. 

1800  Lbs.  Press  urr 

Varying 
Pressures. 

Quantity 
in  Cu.  Ft 

Varying 
Pressures. 

Quantity 
in  Cu    Ft 

Varying 
Pressures. 

Quantity 
in  Cu.  Ft 

300 

100 

1800 

100 

1800 

200 

270 

90 

1620 

90 

1620 

180 

240 

80 

1440 

80 

1440 

160 

210 

70 

1260 

70 

1260 

140 

180 

60 

1080 

60 

1080 

120 

150 

50 

900 

50 

900 

100 

120 

40 

700 

39 

700 

78 

100 

33 

500 

28 

500 

56 

75 

25 

.300 

17 

300 

33 

50 

17 

100 

6 

100 

11 

25 

8 

18 

1 

18 

2 

3 

1 

9 

\ 

9 

1 

TABLE  XIII 

VARIATION  OF  PRESSURE  IN   CYLINDERS 
Under  Varying   Temperatures   and  Constant  Quantity 


Initial  Pressure  at  68°  F. 


Fahrenheit. 

100  Lbs 

300  Lbs. 

1800  Lbs 

120 

109.85 

329  5 

1973 

100 

106.05 

318  2 

1909 

80 

102  .3 

306  8 

1841 

60 

98  48 

295  5 

1773 

40 

95  7 

•JM    I 

1705 

20 

90  91 

272  7 

1636 

0 

87.12 

261  4 

I-itis 

—10 

85.23 

255  .7 

1534 

—20 

83  33 

250  0 

1500 

130 


USEFUL  INFORMATION 


TABLE   XIV 
COMPARISON  OF  DEGREES  CENTIGRADE  AND  FAHRENHEIT. 


Below  Zero. 
C     F 

Above  Zero. 

Above  Zero 
C      F 

Equivalents 
C     F 

300 

—  328 

525 

—  977 

1250 

—  2282 

1 

—  I  8 

150 

—  238 

550 

-  1022 

1275 

—  2327 

2 

—  3  6 

100 

—  14S 

575 

—  1067 

1300 

—  2372 

3 

54 

50 

—  58 

600 

-  1112 

1325 

—  2417 

4 

7  2 

625 

H57 

1350 

2462 

— 

9n 

Above  Zero 

650 

—  1202 

1375 

—  2507^ 

o 
6 

V 

—  10  8 

C 

F 

675 

-  1247 

1400 

—  2552 

7 

-  12  6 

0 

—  32 

700 

-  1292 

1425 

—  2597 

- 

-  14  4 

25 

—  1  1 

725 

—  1337 

1450 

-  2642 

9 

-  16  2 

50 

-  122 

750 

—  1382 

1475 

—  2687 

10 

—  18  0 

75 

—  167 

775 

—  1427 

1500 

—  2732 

11 

—  19  S 

100 

-  212 

800 

—  1472 

1525 

—  2777 

12 

-  21  6 

125 

—  257 

825 

—  1517 

1550 

—  2822 

13 

-  23  4 

150 

—  302 

850 

—  1562 

1575 

-  2867 

14 

-  25  2 

175 

—  347 

875 

—  1627 

1600 

—  2912 

15 

-  27.0 

200 

—  392 

900 

-  1652 

1625 

-2957 

16 

225 

—  437 

925 

—  1697 

1650 

—  3002 

17 

—  30  6 

250 

—  482 

950 

-  1742 

1675 

—  3047 

18 

-  32  4 

275 

—  527 

1000 

—  1832 

1700 

—  3092 

19 

-  34  2 

300 

—  372 

1025 

—  1877 

1725 

—  3137 

20 

-360 

325 

—  617 

1050 

—  1922 

1750 

—  3182 

21 

-  37.8 

350 

—  662 

1075 

—  1967 

1775 

—  3227 

22 

—  39  6 

375 

—  707 

1100 

—  2012 

1800 

—  3272 

r.y 

-  41  4 

400 

—  752 

1125 

—  2057 

1825 

—  3317 

24 

-  43  2 

425 

-  797 

1150 

—  2102 

1850 

—  3362 

25 

—  45  0 

450 

842 

1175 

—  2147 

1875 

—  3407 

475 

—  S87 

1200 

—  2192 

1900 

—  3452 

500 

—  932 

1225 

—  2237 

2000 

—  3632 

TABLE  XV 
WEIGHT  OF  OXYGEN  GAS  DRUMS 


Oxygen- 

Capacity.                   Pressure.                    Weight 

Loir  Pressure.    ! 
High  Pressure. 
High.  Pressure.. 

100  cub.  ft. 
100  cub  ft. 
200  cub  ft. 

300  Ibs 
180011*. 
1800  Ibs. 

150  Ibs. 
125  Ibs. 
150  Ibs. 

USEFUL  INFORMATION 


131 


£  i,   c  " "   3       •«*  t>-       er  t--  c;       -^ 
--^a.o      :2=:^5«-=3«_» 


= 


>»rp  s. 

^  3 


II 


=    2 
'*  = 


132 


N  D  E  X 


A 

C 

Atomic    theory 

13 

Calcium    Carbide 

21 

Atomic    weights    

...  12 

Calorie  :  

31 

Acetylene     

....  23 

Centigrade  ,  

32 

Allovs 

....  41 

Coefficients     of     expansion 

33 

Alloys  —  table    of    

....  42 

Calculations   in   expansion 

33 

Aluminum    

...  43 

Conductivity   of   heat   

34 

Acetylene    generators   

...  44 

Cast  iron  

35 

Assembling   cutting    torch    

....  56 

Cast    iron    welding    

101 

Automatic   Oxygen   regulator   

....  59 

Cast    iron    flux    

88 

Acetylene    Regulator    

....  58 

Copper     

39 

Acetylene  —  oxygen       required 

to 

Copper    flux    

88 

consume   

...  50 

Copper   welding   

104 

Acetylene   in   drums   

....  81 

Carbide    

21 

Acetone      

....  81 

Carbide    to    water   generator    

45 

Adjusting   the  flame   

....  95 

Carbide  —  yield   of    gas    

Aluminum    welding 

105 

Composition    of    sludge    

72 

Air  —  oxygen   from  

....  19 

Cost    of    acetylene    

69 

Clean    oxygen    hose    

80 

B 

Cleaning    the    weld    

89 

Building   in   gear   teeth   _ 

....    4 

Charges    for    welding    service 

84 

Boyles    Law 

25 
...  31 

...  39 
...  40 

Chloride  of  potash  method  of  p 
ducing    oxygen 

ro- 
18 
53 
110 

British   thermal  unit   
Blister     Process    
Brass    

Cutting    torch    ;  
Cutting    iron    and    steel  ".  

Brass  —  welding  
Building  a  furnace  
Beveling 

...104 
...  76 
...  89 
...104 

Cutting   steel    floor   beams    
Cutting    machines    
Cost   of    gas    for    cutting    
Carbon     burning     

115 
113 
_114 
126 

Bronze  —  welding     .'... 

Boiler    making    

...118 

D 

c 

Drip    type    generator    

45 

Comparative   cost  of  cutting   
Chemistry     
Origin    

Dissolved   acetylene    
Defects   of  welds   
Directions     for    carbon    burning 

81 
100 
...126 

Elements    

1  1               Drums    of    acetylene    

81 

Symbols 

11 

Atomic  weights  

12 

F 

Notation     

...  12 

Affinity     

Examples   of   savings   

4 

Atomic    theory    

Elements    

11 

Valence    
Re-action   

I/-               Electrolysis    

19 

Combustion    

|5              Effect    of    temperature    on    pressure  28 

Flame     .. 

.    16 

Exoansion 

...  32 

INDEX 


133 


E 

Expansion — coefficients  of               ...  33 

Expansion — calculating    the    33 

Expansion — precautions  regarding...  91 

Expansion— effects    of    92-120-121 

Economy  of  preheating  94 

Examples    in    welding  107 


Flame 

16 

Fahrenheit   

31 

Ferrous    group    of    metals    . 

35 

Flashing    Back 

50-80 

Fluxes    

87 

For   cast   iron 

88 

For   copper 

83 

Filling  in  holes  

99 

Fabricating    a    bosh    jacket 

119 

G 

Gas- 

Oxygen    

17 

Hydrogen    

20 

Nitrogen     

21 

Acetylene    

23 

Gas  —  weight    of 

21 

Gas  —  quantity  in  drums  

26 

Gas  —  yield    from   carbide 

23 

Gay    Lusac's    Law    

27 

General    notes    on   welding 

89 

H 

Hydrogen 

....  20 

High  pressure  pump 

29 

Heat    

....  30 

Heat    conductivity    

34 

Heat    liberated   by    carbide 

in   wa- 

ter     

44 

High    pressure    torch    

52 

How  and  where  to  preheat 

95 

Handling    the    torch    

% 

Holes  —  filling    in    

99 

Low    pressure    torch  5| 

Loss   of   pressure    in   pipes  „_  70 

Loss  of  pressure  in  valves  and  fit- 
tings   ...  7| 

Leaks   in  oxygen  pipes  „  73 

Lead    burning  ..J06 

Leaks — testing    for   _  73 

Lead  welding   __ _J06 

Liquid    air — oxygen    from    19 

M 

Melals    and    their    properties  35 

Malleable   cast  iron  _ 36 

Malleable   cast   iron   welding   102 

Melting    temperatures    _  39 

Movements  of  the  torch 98 

Machine    for    cutting    _113 

Manganese  dioxide  method  of  pro- 
ducing oxygen  18 


N 


Nitrogen     . 21 

Neutral    flame   ...  ....  95 


O 


ind 


Oxygen    

From   air   

By    electrolysis    _ _ 

From    chloride    of     potash 

manganese- dioxide    18 

Oxyacetylene     cutting     6 

Oxyacetylene    torch   _  50 

Oxygen  required  to  consume  acety- 
lene     5 

Operating    plants    68 


Phases    of    combustion    -   17 

Physics     ,~.  25 

Phneumalics     ~ -  25 

Pressure    regulators    58 


134 


INDEX 


Preheating    furnaces   76 

Protecting     apparatus     77 

Portable    acetylene    drum   plant    81 

Portable    acetylene    generator   plant  83 

Preheating   to   eliminate   defects   94 

Preheating   how    and   where   95 

Puddle-system   1 05 

Preparing    the   joint  122 

Propagation    of    flame    50 


Repairing    locomotive    cylinder    2-3 

Repairing    pump    case 
Reaction 


Steel  

Steel    welding 
Selecting    a    g< 
Sludge — composition 
Scrapping  a  boiler 


Temperature 

Thermometers 

Temperature 

Thermite    

Typical    carbi 

tor     

Torches    

Torches — for    machines 

Testing    pipe    lines    

Time   card   for  welding  shop 
Theory    of    cutting    


u 

Use   of    the   oxyacetylene    torch 

Using    the    cutting    torch    

Unit  of  heat  

Unit — British    thermal    

V 


4 

111 
.  31 
.  31 


14 


Valence    .  . 

Velocity    of    propagation    of    flame  50 
Vulcan    automatic    acetylene    gene- 
rator   ; 6 1 

Vulcan   portable    generator   plant   ...  67 


W 


:  16 

Welding   cranK    snart   
Weight    of    gases    

0-  1  U/ 

21 

Wrought    iron   

37 

S 

Welding— 

Iron    and    steel    

101 

38 

Cast   iron   

101 

101 

Malleable   cast   iron   

102 

nerator    47 

Copper 

104 

sition    of    72 

Brass    

104 

jiler  116 

B  ronze  .  

104 

Aluminum 

105 

T 

Lead 

106 

Welding  rods  and  fluxes  

87 

to  cut  plates  7 

Welding    table    

74 

31 

Welding  —  examples    in    

107 

31 

Auto    cylinders    

108 

f    melting    39 
43 

Auto   springs   
Crack    in    boiler    

109 
124 

le    to    water    genera- 

Patch  in  boiler  

124 

45 

Flues    in    boiler    

125 

50 

Welding   pieces    of    differenl 

thick- 

L:  e-7 

ness     . 

119 

73 

86 

110 


Yield    of    gas    from    carbide 


23 


Pure  Calcium  Carbide 

*  <r"pHE  purity  of  Acetylene  goes  hand  in  hand  with 
the  purity  of  Carbide,  and,  just  as  preventive  is 
better  than  cure,  so  to  use  only  an  excellent  quality  of 
Carbide,  thus  avoiding  impurities,  is  clearly  better  than 
to  use  a  poorer  grade  which  is  sure  to  result  in  the 
formation  of  impurities.11 

—PROF.  GEORGE  GILBERT  POND, 

Leading  Authority  on  Acetylene. 

We  thoroughly  agree  with  Professor  Pond,  that  only  Car- 
bide of  the  Greatest  Purity  should  be  made.  Therefore,  we 
handle  only  the  one  grade — that  the  best  it  is  possible  to 
produce.  Our 

^^P^-kL 

t     TRADE  ^C^^tttC^    MARK 

distinguishes  pure  from  impure  Carbide,  and  stands  for  a  defi- 
nite, guaranteed  gas  yield. 

American  Carbolite  Sales  Co. 

DISTRIBUTORS 
Warehouses  Everywhere  DULUTH,  MINNESOTA 


A  Vulcan 


ill 


Welding  Torch,  Acety- 
lene Generator,  or  Com- 
plete Welding  Plant  is 
far  in  advance  of  the 
average  Welding  appa- 
ratus. All  SPECIAL 
FEATURES  are  pro- 
tected by  patents.  Cost 
is  lowest  consistent 
with  greatest  efficiency 
known. 

VULCAN  PROCESS  CO. 


Factory  and  Sales  Room  25th  and  University  Ave.  S.  E. 

MINNEAPOLIS,  MINN. 


Pure  Compressed 
Electrolytic  Oxygen 
Highest  Grade  Vulcan 

Oxy  -  Acetylene 
Welding  Supplies 

There  are  some  cheap  imitations  of  Vulcan  Welding 
supplies.  Do  not  accept  them.  If  your  dealer  does 
not  carry  Vulcan  supplies,  send  order  direct  to  us,  and 
we  will  make  shipment  same  day  order  is  received.  All 
our  welding  rods,  including  the  cast  iron,  steel,  bronze, 
aluminum  and  aluminum  solder,  rods  are  made  up  after 
our  own  formulaes,  and  have  been  adopted  only  after 
years  of  experimenting  and  testing.  Our  fluxes  for 
cast  iron  welding,  aluminum  welding  or  brass  and  bronze 
welding  are  extra  strength  and  when  using  them,  direc- 
tions should  be  followed  closely. 

We  maintain  a  complete  job  repair  plant  in  connec-     i 
tion. 

NORTHERN  WELDING  COMPANY 

Manufacturers  of 
Complete  Welding  Equipment  and  Supplies 

25th  and  University  Ave.  S.  E.          Minneapolis,  Minn. 


__ 

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